Answer :

Given,

S_{n} = 280, n = 4 and common difference is -20.

Let the first term be a.

Since the sum of n terms is

S_{n =}

Where,

a = First term of AP

d = Common difference of AP

and no of terms is ‘n’

_{}So sum of 4 terms S_{4}

]

280 = 2× [2a + 3 × (-20)]

140 = 2a – 60

2a = 140 + 60

2a = 200

a = 100

a_{1} = a = 100

a_{2} = a_{1} + d = 100 - 20 = 80

a_{3} = a_{2} + d = 80 - 20 = 60

a_{4} = a_{3} + d = 60 - 20 = 40

Hence, The value of prizes are 100, 80, 60 and 40.

Rate this question :

A sum of 280 is tRajasthan Board Mathematics

If the sum of theRajasthan Board Mathematics

Find the sum of aRajasthan Board Mathematics

Find the sum of tRajasthan Board Mathematics

Find the sum of tRajasthan Board Mathematics

Find the sum of tRajasthan Board Mathematics

Find the sum of tRajasthan Board Mathematics

Find the number oRajasthan Board Mathematics

The first term anRajasthan Board Mathematics

If the sum of n tRajasthan Board Mathematics