Question

a sum of rupees 700 is to be used to give seven cash prizes to students of a school for their overall academic performance if each price is rupees20 less than its preceding price find the value of each of the prices​

Answer 1

Given:

First element = a

Common difference (d) = -20

No. of elements (n) = 7

Sum of all elements (s) = 700

Note: Consider the series as an AP series.

Now:

$\implies$ S = n/2 (2a+(n-1)d)

$\implies$ 700 = 7/2 [2a+(7-1)(-20)]

$\implies$ 200 = 2a-120

$\implies$ 320 = 2a

$\implies$ a = 160

Hence:

The series will be:

160, 140, 120, 100, 80, 60 and 40.

Answer 2

Heya...

Solution is given above...

Now series will be :-

160, 140,120,100,80,60,40,20...