CHAPTER-5 ARITHMETIC PROGESSIONS
QUESTION -5
The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.
AMSWER:
Given that,
a = 5
l = 45
Sn = 400
n = 16
l = a + (n − 1) d
45 = 5 + (16 − 1) d
40 = 15d
