Question

Find the sum of 17th terms of the ap 5,9,13,17...

Answer 1

a=5

d=9-5

• d=4
• sn =n/2{2a+(n-1)d
• sn=17/2{2(5)+16(17-1)4
• 17/2{10+16(4)
• 17/2(10+64)
• 17/2(74)= 37
• 17×37= 629

Answer 2

Sum of 17 term of AP, 5,9,13,17...    is 629

Given:

5,9,13,17...  is Arithmetic Progression

To find:

The sum of 17 terms of the ap

Solution:

Given 5,9,13,17...  is Arithmetic Progression

Here, first term a = 5

Common difference d = 9 - 5 = 4

As we know the formula for Sum of n terms in AP is given by

                     ⇒ S$_{n}$ = n/2 [ 2a+(n-1)d ]

Sum of 17 terms S₁₇ = 17/2 [ 2a + (17 -1)d ]

= 8.5 [ 2a+ 16d ]

= 8.5 [ 2(5) + 16(4) ]

= 8.5 [ 10 + 64 ]  

= 8.5 [74]

= 629

Sum of 17 term of AP, 5,9,13,17...   is 629

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