You are 26. 2 years ago you were 24, which is a multiple of 6 Last year you were 25, which is a multiple of 5. To work it out, let your age be N: N - 2 = 6p N - 1 = 5q N < 50 Solve the two equations for N N = 6p + 2 N = 5q + 1 Equate the two expressions for N 6p + 2 = 5q + 1 1 = 5q - 6p Write 6 in terms of 5 as 5+1 1 = 5q - (5+1)p 1 = 5q - 5p - p Divide thru by 5 1/5 = q - p - p/5 Isolate the fractions: p/5 - 1/5 = q - p The right side is a positive integer, therefore so is the left side. Let that positive integer be A p/5 - 1/5 = A also q - p = A p - 1 = 5A p = 5A + 1 Since q - p = A q - (5A + 1) = A q - 5A + 1 = A q + 1 = 6A q = 6A - 1 So we have p = 5A + 1 q = 6A - 1 Since N < 50 and N = 6p + 2 6p + 2 < 50 6p < 48 p < 8 and since p = 5A + 1 5A + 1 < 8 5A < 7 A < 7/5 Since A is a positive integer, it can only be 1. So A = 1 So p = 5A - 1 = 5(1) - 1 = 5 - 1 = 4 So N = 6p + 2 N = 6(4) + 2 N = 24 + 2 N = 26 Edwin