Question

Johann borrows money from his parents to purchase a bike. He makes weekly payments to his parents to repay the money

borrowed. The total amount of money repaid at the end of week n can be represented using the recursive formula a, = 10+ an-1-
At the end of the fourth week, Johann had repaid his parents a total of $55. What is the total amount Johann had repaid his
parents at the end of the first week?
o $10
$20
$25
$35​

Answer 1

$25

Explanation:

An = 10 + An-1

At the end of 4th week ; amount repaid = $55

A4 = 10 +

An = a + (n - 1)d

n = 4

A4 = 10 + (4 - 1)d

55 = 10 + 3d

55 - 10 = 3d

45 = 3d

d = 15

Hence, at the end of first week :

A1 = a + d

$10 + $15

= $25