Math, asked by atul5843, 9 months ago

On each birthday , john received from his father rs 5 for each year of his age . find the total sum john had received by the time he was 21 years old.

Answers

Answered by parthpardesi
0
Here is your answer

5rupees each year * 21 years
= 5*21
= 105

Answer
John recieved ₹105 by the time he was 21 yrs old
Answered by edumenino2007
0

Sn= ? , a= 5, d= 5 , n = 21

Sn = n÷2 [2a +(n -1 )(d)]

Sn = 21÷2[2(5)+21- 1 (5)]

Sn =21÷ 2[(10)+20(5)]

Sn = 21÷2( 10+ 100 )

Sn = 21÷2(110)

Sn =21 × 55

Sn = 1,155

Therefore John recieved a total sum of Rs 1,155 by the time he was 21 years old.

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