Question

For what calue of n are the nth terms of the following a.p.s the same - 1. 15,12,9..... and 2. 9,7,5....

Answer 1

Given ap's are _1,15,12,9....... 2,9, 7,5...... a=-1 ,d=15-(-1) =15+1=16 A=2. D=9-2=7 LET nthterm = nthterm a+n-1)d = A+ n-1)D -1+n-1)16 = 2+n-1)7 16n-17 =7n-5 16n-7n =-5+17 9n =12 n= =12/9