ICSE ICSE Class 8 - CISCE Question Bank Solutions for Mathematics

Find the area of the circle, length of whose circumference is equal to the sum of the lengths of the circumferences with radii 15 cm and 13 cm.

A contractor undertakes to dig a canal, 6 kilometers long, in 35 days and employed 90 men. He finds that after 20 days only 2 km of the canal has been completed. How many more men must be employed to finish the work on time?

90 men can complete a work in 24 days working 8 hours a day. How many men are required to complete the same work in 18 days working `7 1/2` hours a day?

Twelve typists, all working with the same speed, type a certain number of pages in 18 days working 8 hours a day. Find, how many hours per day must sixteen typists work in order to type the same number of pages in 9 days?

A can do a piece of work in 10 days and B in 15 days. How long will they take together to finish it?

A and B together can do a piece of work in `6 2/3` days, but B alone can do it in 10 days. How long will A take to do it alone?

A can do a work in 15 days and B in 20 days. If they together work on it for 4 days; what fraction of the work will be left?

A, B, and C can do a piece of work in 6 days, 12 days, and 24 days respectively. In what time will they altogether do it?

A and B working together can mow a field in 56 days and with the help of C, they could have mowed it in 42 days. How long would C take by himself?

A can do a piece of work in 24 days, A and B can do it in 16 days and A, B, and C in `10 2/3`  days. In how many days can A and C do it working together?

A can do a piece of work in 20 days and B in 15 days. They worked together on it for 6 days and then A left. How long will B take to finish the remaining work?

A can finish a piece of work in 15 days and B can do it in 10 days. They worked together for 2 days and then B goes away. In how many days will A finish the remaining work?

A can do a piece of work in 10 days; B in 18 days; and A, B, and C together in 4 days. In what time would C alone do it?

A can-do `1/4` of work in 5 days and B can do `1/3` of the same work in 10 days. Find the number of days in which both working together will complete the work.

A and B can do a work in 8 days; B and C in 12 days, and A and C in 16 days. In what time could they do it, all working together?

A and B complete a piece of work in 24 days. B and C do the same work in 36 days; and A, B, and C together finish it in 18 days. In how many days will:
(i) A alone,
(ii) C alone,
(iii) A and C together, complete the work?

A and B can do a piece of work in 40 days; B and C in 30 days; and C and A in 24 days.

1. How long will it take them to do the work together?
2. In what time can each finish it working alone?

A can do a piece of work in 10 days, B in 12 days, and C in 15 days. All begin together but A leaves the work after 2 days and B leaves 3 days before the work is finished. How long did the work last?

Two pipes P and Q would fill an empty cistern in 24 minutes and 32 minutes respectively. Both the pipes being opened together, find when the first pipe must be turned off so that the empty cistern maybe just filled in 16 minutes.

Multiply: 5x² - 8xy + 6y² - 3by - 3xy