Answer:
$25
Step-by-step 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