5 consecutive multiples of 4 = 4x, 4 (x + 1), 4 (x + 2), 4 (x + 3) and 4 (x + 4) ⇒ 4 [x + x + 1 + x + 2 + x + 3 + x + 4] = 100 ⇒5x+10=
100
4
=25 ⇒x=3 ∴ Largest number = 4 (x + 4) = 4 × 7 = 28 For series S2, Second lowest number = 28 – 6 = 22 ∴ 4 consecutive even numbers are : 20, 22, 24, 26 Required average =