Question

Find the sum of first 10t terms of the AP 2, 7,12..... so on

Answer 1

Hola there,

A.P. = 2, 7, 12...

a = 2

d = 7 - 2 = 5

n = 10

Sn = n/2(2a + (n - 1)d)

= 10/2(2×2 + (10 - 1)5)

= 5(4 + 45)

= 5×49

= 245 ...Ans

Hope this helps...:)

Answer 2

Sum of nth term of an AP is = n/2[2a + (n-1)d]

Given =>

a = 2
d = 5
n = 10

So, according to formula =>

= n/2[2a + (n-1)d]

= 10/2[2(2) + (10-1)5

= 5[4 + 9(5)

= 5[4+ 45]

= 5[49]

= 245