What should come in place of question mark (?) in the given number series ?
For the following questions answer them individually
A is thrice as efficient as B and takes 10 days less to do a piece of work than B takes to do the same work. In how many days, B alone can finish the whole work ?
The compound interest on a certain sum for 2 years at 10% per annum is Rs.525/Â. The simple interest on the same sum for double the time at half the rate percent per annum is...........
What approximate value will come in place of question mark (?) in the given question ? (You are not expected to calculate the exact value.)