Question

The first and last term of an AP are1 and 11 if the sum of all its term is 36 then find the number of terms in the AP

Answer 1

Step-by-step explanation:

a = 1 {a is the first term}

an = 11 {an is the last term}

Sn = 36 {Sn is the sum of n terms}

Sn = n/2 (a +an) {n is the number of terms}

36 = n/2(1+11)

36 = n/2×12

36 = n×6

6n = 36

n= 36/6

n= 6

hope it helps you..