Answer:
600 - Y=18.75x , 24 months
Step-by-step explanation:
Given: Clarissa's sister makes weekly installment payments for a motorized scooter she purchased from a friend. She purchased the motorized scooter for $600 and is paying $18.75 a week to her friend until it is paid off.
To Find: the equation and solution for the number of months, x, it takes her to have $150 left to pay.
Solution: Total cost of scooter=
600
monthly payment =

let payment left to pay = 
equation of number of months and total payment left to pay
-
=

putting values in equation
=150

= 
= 24
So, it takes her 24 months when
is left to pay