Question

Victor puts a certain amount of money in his piggy bank each month. In the first month, he saves 4 dollars, in the second month he saves 8 dollars, and 12 dollars in the third month. If he saves in the same order for 6 months, how much money will he save at the end?

Answer 1

Money saved in the first month = 4 dollars

Money saved in the second month = 8 dollars

Money saved in the third month = 12 dollars

Hence, the sequence of Victor's savings =

4, 8, 12, ...


$Commondifference:$

Let us find the common difference between the terms.

Difference between the second and the first terms = 8 – 4 = 4

Difference between the third and the second terms
= 12 – 8 = 4

Hence, common difference = 4

Therefore, the amount of savings is 4, 8, 12, 16, 20, 24.

∴ Sum of savings = 4 + 8 + 12 + 16 + 20 + 24

Taking 4 common, we get:

Sum = 4 × ( 1 + 2 + 3+ 4 + 5 + 6 )

= 4 × 21

= 84

Hence, he will save 84 dollars at the end of 6 months.