If  $$ \ {xy\over x+y}= a, $$ $${xz\over x+z}=b $$ and $$ {yz\over y+z} =c $$  where a, b, c are all non – zero numbers, then x equals to

Rajesh can do a work in 6 days and Vikram can do the same work in 5 days. The contract for the work is of Rs. 3300 . How much shall Vikram get if both of them work together?

The ratio of ages of A and B 4 years ago was 5 : 3. The sum of present ages of A, B and C is 80 years. If present age of C is equal to sum of present ages of A and B. find the present age of A.

A trader bought 120 kg of potato at 24/kg. He sold 80 kg of it at 50% profit and the balance at 25% low. Find the total profit or loss? 

a, b, c, d, e, f, g are consecutive even numbers. j, k, l, m, n are consecutive odd numbers. The average of all the numbers is: 

The cost of 6 dozen apples and 8 dozen bananas is ₹ 1400. what will be the cost of 15 dozen apples and 20 dozen bananas?

Direction: What should come in place of the question mark (?) in the following number series?
0.5, 2, 9, 35, 104, ?