Question

shakeela put 100RS into her daughters money box when she was 1 year old,150rs on her 2nd birthday 200rs on her 3rd birthday and will continue in the same way .How much money will be collected in the money box by the time has daughter is 21 year old​

Answer 1

Answer:

Rs12600

Step-by-step explanation:

here using the sum rule for arithmetic progression

• on 1st birthday she put rs100so
• first term (a)=100 since she put the money increasing 50 rupees per year so difference (d) = 50
• no of terms 21 because she put money for 21 years so using sum rule
• S21=n/2 (2a+(n-1)d)
• then you get the answer
• Rs12600

Answer 2

Answer

==>

Rs 12600

Given

==>

Shakeela put money on

1st birthday = 100

2nd birthday = 150

3rd birthday = 200

Total money on 21st birthday = S²¹

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Solution

==>

So from above we got an AP sequence.

100 , 150 , 200 ...............

Now we will find the important terms from the above provided AP sequence.

Total terms in AP ( n ). = 21

First term of AP ( a ). = 100

Common difference (.d ) = 50

Sum of all terms ( Sn). = ?

Now we have to find total amount that will get collected in the money box

Formula used

==>

Sn = n/2[2a + (n -1 ) d]

Calculation

==>

Putting all the required values in formula.

➜ S²¹ = 21/2[2 × 100+ (21-1)50]

➜ S²¹ = 21. × 1200/2

➜ S²¹ = 21 × 600

➜ S²¹ = 12600

So , total amount in money box will be Rs 12600

Hope it helps