Secondary School (English Medium) (5 to 8) Class 8 - CBSE Question Bank Solutions for Mathematics

A, B and C can reap a field in \[15\frac{3}{4}\] days; B, C and D in 14 days; C, D and A in 18 days; D, A and B in 21 days. In what time can A, B, C and D together reap it?

A and B can polish the floors of a building in 10 days. A alone can do \[\frac{1}{4}\] th of it in 12 days. In how many days can B alone polish the floor  ?

What must be added to the following expression to make it a whole square? 

4x² − 12x + 7

What must be added to the following expression to make it a whole square? 

4x² − 20x + 20

Convert the following percentage to fractions and ratio:
25%

Convert the following percentage to fractions and ratio:
2.5%

Convert the following percentage to fractions and ratio:

0.25%

Convert the following percentage to fractions and ratio:
0.3%

Convert the following percentage to fractions and ratio:
125%

A and B can finish a work in 20 days. A alone can do \[\frac{1}{5}\]  th of the work in 12 days. In how many days can B alone do it?

A and B can do a piece of work in 20 days and B in 15 days. They work together for 2 days and then A goes away. In how many days will B finish the remaining work?

A can do a piece of work in 40 days and B in 45 days. They work together for 10 days and then B goes away. In how many days will A finish the remaining work? 

Aasheesh can paint his doll in 20 minutes and his sister Chinki can do so in 25 minutes. They paint the doll together for five minutes. At this juncture they have a quarrel and Chinki withdraws from painting. In how many minutes will Aasheesh finish the painting of the remaining doll?

A and B can do a piece of work in 6 days and 4 days respectively. A started the work; worked at it for 2 days and then was joined by B. Find the total time taken to complete the work.

6 men can complete the electric fitting in a building in 7 days. How many days will it take if 21 men do the job?