Unitary Method ICSE Class-7th Concise Selina Mathematics Solutions Chapter-7. We provide step by step Solutions of Exercise / lesson-7 Unitary Method for ICSE Class-7 Concise Selina Mathematics. Our Solutions contain all type Questions with Exe-7 A , Exe-7 B and Exe-7 C, to develop skill and confidence. Visit official Website CISCE for detail information about ICSE Board Class-7.
Unitary Method ICSE Class-7th Concise Selina Maths Solutions Chapter-7
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Exercise – 7 A of Unitary Method Solved Questions
Question 1.
Weight of 8 identical articles is 4.8 kg. What is the weight of 11 such articles ?
Answer-1:
Weight of 8 articles = 4.8 kg
Weight of 1 article = 4.8/8 kg
and weight of 11 articles = (4.8/8) / 11 kg
= 0.6 x 11 = 6.6 kg
Question- 2.
6 books weigh 1 .260 kg. How many books will weigh 3.150 kg ?
Answer-2:
1 kg 260 g or 1.260 kg no.of.books = 6
and in 1 kg. no. of books = 6/1.260
and in 3.150 kg no.of.books = 6×3.150/1.260
=6×3150 / 1260
=3150 / 210
= 15 books
Question 3.
8 men complete a work in 6 hours. In how many hours will 12 men complete the same work ?
Answer:
8 men can complete a work in = 6 hours
1 man can complete the work in = 6×8 hours
12 men can complete the work in = 6×8 / 12
= 4 hours
Question 4.
If a 25 cm long candle burns for 45 minutes, how long will another candle of the same material and same thickness but 5 cm longer than the previous one, burn ?
Answer:
25 cm long candle burn in = 45 minutes
1 cm long candle will burn in = 45/25 minutes
25 + 5 = 30 cm long candle will burn in
=45×30 / 25 minutes
= 54 minutes
Question 5.
A typist takes 80 minutes to type 24 pages. How long will he take to type 87 pages ?
Answer:
For typing 24 pages, time is required = 80 minutes
For typing 1 page, time is required = 80 /24 minutes
and for typing 87 pages, time is required
=80×87 / 24 minutes
= 290 minutes
Question 6.
Rs. 750 support a family for 15 days. For how many days will Rs. 2,500 support the same family ?
Answer:
Rs. 750, can support a family for = 15 days
Rs. 1 will support for = 15/ 750 days
and Rs. 2,500 will support for = 15×2500 / 750 days
= 50 days
Question 7.
Answer:
400 men have provisions for = 23 weeks
1 man will have provisions for = 23 x 400 weeks
and 400 + 60 = 460 men will have provisions for = 23×400 / 460 weeks
= 20 weeks
Question 8.
200 men have provisions for 30 days. If 50 men left, the same provisions would last for the remaining men, in how many days?
Answer:
200 men have provisions for = 30 days
1 man will have provisions for = 30 x 200 days
200 – 50 = 150 men will have provisions for = 30×200 / 150 days
= 40 days
Question 9.
Answer:
8 men can finish a provision in = 40 days
1 man will finish in = 40 x 8 days
10 ( 8 + 2 ) men will finish in = 40×8 /10
= 32 days
Question 10.
If interest on Rs. 200 be Rs. 25 in a certain time, what will be the interest on Rs 750 for the same time ?
Answer:
Interest on Rs, 200 is = Rs. 25
Interest on Rs, 1 will be = Rs. 25 / 200
interest on Rs. 750 = Rs. 25×750 / 200
= Rs. 93.75
Question 11.
Answer:
3 dozen = 3 x 12 = 36 eggs,
3 scores = 3 x 20 = 60
The cost of 36 eggs is = Rs. 90
The cost of 1 egg will be = Rs. 90 / 36
∴ Cost of 60 eggs will be = Rs (90×60 ) / 36
= Rs. 150
Question 12.
If the fare for 48 km is Rs. 288, what will be the fare for 36 km ?
Answer:
Fare for 48 km = Rs. 288
fare for 1 km = Rs. 288×36 /48
= Rs. 216
Question 13.
What will be the cost of 3.20 kg of an item, if 3 kg of it costs Rs. 360 ?
Answer:
Cost of 3 kg of an item = Rs. 360
Cost of 1 kg of the item = Rs. 360 / 3
∴ Cost of 3.20 kg of the item = Rs. 360 x 3.20 / 3
=384 Rs
Question 14.
If 9 lines of a print, in a column of a book contains 36 words. How many words will a column of 51 lines contain ?
Answer:
In 9 lines of print, words are = 36
In 1 line of print, words will be = 36 / 9
∴ in 51 lines of print, words will be = 36 x 51 / 9
= 204
Question 15.
125 pupil have food sufficient for 18 days. If 25 more pupil join them, how long will the food last now ? What assumption have you made to come to your answer ?
Answer:
Pupils in the beginning = 125
More pupils joined = 25
Total pupils = 125 + 25 = 150
Food is sufficient for 125 pupils for = 18 days
Food will be sufficient for 1 pupil for = 18 x 125 days
(less pupil more days)
and food will be sufficient for 150 pupils = 18×125 /150 days
(more pupil more days)
=18×5 / 6
= 15 days
Question 16.
A carpenter prepares a new chair in 3 days, working 8 hours a day. At least how many hours per day must he work in order to make the same chair in 4 days ?
Answer:
A chair is completed in 3 days working per day = 8 hours
Then their will be completed in 1 day working for = 8 x 3 hours per day (less days more hours)
and it will be completed in 4 days working for = 8×3 / 4
=6 hours / day
Question 17.
A man earns ₹5,800 in 10 days. How much will he earn in the month of February of a leap year?
Answer:
Leap year has 29 days in the month of February.
Man earns in 10 days = ₹ 5800
Man earns in 1 day = ₹ 5800 / 10
∴ Man earns in February month of leap year = ₹ 5800 x 29 / 10
= ₹ 16820
Question 18.
A machine is used for making rubber balls and makes 500 balls in 30 minutes. How many balls will it make in 3
Answer:
30 minutes = 30 / 60
= 1/2 hours
In 1/2 hours ball makes by machine = 500
In 1 hours balls makes by machine = 500×2/1
=1000 balls
∴ In 3 1⁄2 = (7/2) hours, Balls make by machine
= 500 × 2 × 7 / 2
= 3500 balls
Question 19.
In a school’s hostel mess, 20 children consume a certain quantity of ration in 6 days. However, 5 children did not return to the hostel after holidays. How long will the same amount of ration last now?
Answer:
Total number of children = 20
20 children consume a certain quantity of ration in = 6 days
1 children consume a certain quantity of ration in = 6 x 20 days
but 5 children did not return to the hostel after holidays.
Then number of children in hostel = 20-5 = 15
Hence, 15 children consume certain quantity 6×20 of ration in = 6×20 / 15 days
= 8 days
Exe – 7 B Unitary Method 6th Class ICSE
Question 1.
Answer:
Question 2.
3
Answer:
Question 3.
A wrist watch loses 10 sec in every 8 hours; in how much time will it lose 15 sec. ?
Answer:
Question 4.
In 2 days and 20 hours, a watch gains 20 sec ; find how much time will the watch take to gain 35 sec. ?
Answer:
Question 5.
50 men mow 32 hectares of land in 3 days. How many days will 15 men take to mow it?
Answer:
Question 6.
The wages of 10 workers for a six days week are Rs, 1,200. What are the one day wages: (i) of one worker ? (ii) of 4 workers?
Answer:
Question 7.
If 32 apples weigh 2 kg 800 g. How many apples will there be in a box, containing 35 kg of apples ?
Answer:
Question 8.
A truck uses 20 litres of diesel for 240 km. How many litres will be needed for 1200 km?
Answer:
Question 9.
A garrison of 1200 men has provisions for 15 days. How long will the provisions last if the garrison be increased by 600 men ?
Answer:
Question 10.
A camp has provisions for 60 pupil for 18 days. In how many days, the same provisions will finish off if the strength of the camp is increased to 72 pupil ?
Answer:
Exe – 7 C Unitary Method Questions Solved
Question 1.
A can do a piece of work in 6 days and B can do it in 8 days. How long will they take to complete it together ?
Answer:
Question 2.
A and B working together can do a piece of work in 10 days B alone can do the same work in 15 days. How long will A alone take to do the same work ?
Answer:
Question 3.
A can do a piece of work in 4 days and B can do the same work in 5 days. Find, how much work can be done by them working together in : (i) one day (ii) 2 days.
What part of work will be left, after they have worked together for 2 days ?
Answer:
Question 4.
A and B take 6 hours and 9 hours respectively to complete a work. A works for 1 hour and then B works for two hours.
(i) How much work is done in these 3 hours ?
(ii) How much work is still left ?
Answer:
Question 5.
A, B and C can do a piece of work in 12, 15 and 20 days respectively. How long will they take to do it working together ?
Answer:
Question 6.
Two taps can fill a cistern in 10 hours and 8 hours respectively. A third tap can empty it in 15 hours. How long will it take to fill the empty cistern, if all of them are opened together ?
Answer:
Question 7.
Mohit can complete a work in 50 days, whereas Anuj can complete the same work in 40 days.
Find:
(i) work done by Mohit in 20 days.
(ii) work left after Mohit has worked on it for 20 days.
(iii) time taken by Anuj to complete the remaining work.
Answer:
Question 8.
Joseph and Peter can complete a work in 20 hours and 25 hours respectively.
Find :
(i) work done by both together in 4 hrs.
(ii) work left after both worked together for 4 hrs.
(iii) time taken by Peter to complete the remaining work.
Answer:
Question 9.
A is able to complete 
Find:
(i) how much work can A do in 1 hour ?
(ii) how much work can B do in 1 hour ?
(iii) in how much time will the work be completed, if both work together.
Answer:
Question 10.
Shaheed can prepare one wooden chair in 3 days and Shaif can prepare the same chair in 4 days. If they work together, in how many days will they prepare :
(i) one chair ?
(ii)14 chairs of the same kind?
Answer:
Question 11.
A, B and C together finish a work in 4 days. If A alone can finish the same work in 8 days and B in 12 days, find how long will C take to finish the work.
Answer:
— End of Unitary Method ICSE Class-7th Solutions :–
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