A sum of Rs 700 is to be used to give seven cash prizes to students of a school for their overall academic performance. If each prize is Rs 20 less than its preceding prize, find the value of each of the prizes.

Explanation

Here, we are given,

`S_7 = 700, n = 7 and d = -20`

We know,
`S_n = n/2(2a+(n-1)d)`

`700 = 7/2(2a+6(-20))`

`200 = 2a-120=>a = 320/2 = 160`

So, `a_1 = 160`

`a_2 = 160-20 = 140`

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