A, B, C and D are distinct positive integers such that the product AB = 60, the product CD = 60 and A - B = C + D. What is the value of A?

Use substitution to get the values for A, B, C, D:

A = 20 and B = 3 and C = 5 and D = 12 A = 20 and B = 3 and C = 12 and D = 5