number pairs

Consider the pair of numbers (28,168) and (26,132).If you divide the product of two numbers in any pair by the sum of those two numbers, you will get the same result in in each case.
Take the first pair (28,168). Product = 28 x 168 = 4704.Sum = 28 + 168 = 196.
                                           Product /Sum =4704/196 =24.
Take the second pair (26,312). Product = 26 x 312 =8112. Sum =26 + 312 = 338.
                                                Product/Sum =8112/338 = 24.

We get same result  24 in both the cases.Now, can you suggest any other pair of numbers so that product of two numbers when divided by the sum of two numbers leaves 24 as answer?

perfect square number

A,B,C and D represents four different digits. Find the values A,B,C and D if each of 5AABBCCAA and AABBDDCC5 is a perfect square number.

smallest number 4

Find the smallest number which when divided by 6183,5724 and 7812 leaves 3816,4275 and 2187 respectively as remainders.