Question

in an ap, if d=2.6 ,n = 8 and an = 22.4, then A is equal to

1. 5.2
2.4.6
3. 4.2
4. 4

and pls show how to do it..

Answer 1

In an AP , An = a + (n-1)d

Here , d =2.6 , n =8 and An = 22.4

Applying formula,

22.4 = a + (8-1)2.6

22.4 = a + 7×2.6

a = 22.4 - 18.2

a = 4.2

Answer 2

Given

d=2.6

n=8

tn=22.4

a=?

Explanation

in an Ap(arithmatic progression)

tn = a +(n-1)d

22.4=a+(8-1)2.6

= a+7x2.6

= a+ 18.2

a = 22.4-18.2

$\boxed{\textbf{\large{a=4.2}}}$

option (3) is correct