Question

Find the sum of last 7 terms from the end of an



a.P 34,32,30,...8

Answer 1

28 26 24 22 20 18 16

Answer 2

Given,

First term (a) = 34

Last term (l) = 8

$s_{n} = ( \frac{n}{2} ) |a + l|$

$s_{7} = ( \frac{7}{2} |34 + 8|$

$s_{7} = ( \frac{7}{2} ) \times 42$

$s_{7} = (7 \times 21)$

$s_{7} = (147)$