Question

Find the 17th term from the end of the AP:1,6,11,16.... 201,216

Answer 1

first term (a) = 1
second term (a2) = 6
common difference = a2 - a = 6 - 1 = 5
last term (l) = 216
for 17th term from end we use
An = l - (n - 1)d
A17 = 216 - (17 - 1)5
A17 = 216 - 16 × 5
A17 = 216 - 80
A17 = 136
Ans. 17th term from the end = 136