Math, asked by samiduraisamidurai85, 2 months ago

find the sum of first 20 terms of the series 48+56+64...​

Answers

Answered by AllenGPhilip
16

Answer:

S₂₀ = 2,480

Step-by-step explanation:

Have to find the sum of first 20 terms of the series 48,56,64

First term = t₁ = 48

Difference = d = 8

20'th term = t₂₀ = a+19d

t₂₀ = 48+(19×8)

t₂₀ = 48+152 = 200

Sum of first 20 terms = ⁿ/₂(t₁+t₂₀)

n= 20

t₁=48

t₂₀=200

S₂₀ =  ²⁰/₂(48+200)

S₂₀ = ²⁰/₂(248)

S₂₀ = 2,480

Answered by shrutiraut75
1

The given series is: 48+56+64...​

To find : S_{20}

Solotion:

We know that,

S_{20} = \frac{n}{2} [ 2a + (n-1)d ]

Here, n = 20

         a = 48

         d = 56-48

            =8

So,

S_{20} = \frac{20}{2} [2(48) + (19-1) 8 ]

      = 10 [ 98 + 152 ]

       = 10 (250)

       = 2500

Therefore, sum of 20th terms of the given series is 2500.

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