Answer:
$6,427.99
Step-by-step explanation:
-We first find the effective annual interest rate as follows:

#We the use this rate to find the compounded amount after 18 years:

Hence, the amount after 18 years is $6,427.99
So, the age of the aunt is 57 which is 17 years above 40 and the age of west is >>x-14=43 >> 43 which is 17 years below 60
He pays $53.99 hope that help you
12.826+2.93= 15.756
Since you have to round it, your final answer would be 15.8