The average of four consecutive odd numbers A,B, C and D respectively is 24. What is the product of B and D ?

Solution
Let the four consecutive odd numbers be a, a+2, a+4 and a+6.

So, their sum is 4a+12 = 96

Or a = 21

So, the four odd numbers are 21,23,25 and 27

So, the required product is 23*27 = 621