Question

I need help for a test pla

Answer 1

Option C:

161

Solution:

Given data:

$\sum_{n=2}^{8}-2+5 n$

To solve this expression:

$\sum_{n=2}^{8}-2+5 n$

Summation means sum of all the numbers.

Substitute n = 2 in the summation.

$-2+5(2) = -2+10=8$

Substitute n = 3 in the summation.

$-2+5(3) = -2+15=13$

Substitute n = 4 in the summation.

$-2+5(4) = -2+20=18$

Substitute n = 5 in the summation.

$-2+5(5) = -2+25=23$

Substitute n = 6 in the summation.

$-2+5(6) = -2+30=28$

Substitute n = 7 in the summation.

$-2+5(7) = -2+35=33$

Substitute n = 8 in the summation.

$-2+5(8) = -2+40=38$

Sum of all numbers = 8 + 13 + 18 + 23 + 28 + 33 + 38

                                 = 161

$\sum_{n=2}^{8}-2+5 n=161$

Option C is the correct answer.