Question

Find the value of a₂₅ – a₁₅ for the AP: 6, 9, 12, 15, ………..

Answer 1

a = 6, d = 3 ;

a₂₅ = 6 + 24(3) = 78

a₁₅ = 6 + 14(3) = 48 ;

∴ a₂₅ – a₁₅ = 78 – 48

= 30