Question

Marcus is going to start saving $20 every month to buy

a stereo. His parents gave him $10 for his birthday to
open his savings account.
Exploration:
1.
Write an equation that represents Marcus's savings
account balance x months after he began saving. Let
x= the number of months and y= the savings account
balance.

Answer 1

y = $10 + I

where I = PRT/100

P = $10, R = $20 T = x

Explanation:

I represents the Simple Interest formula

P is the Principal or the Money used to start the savings account.

R represents the rate which in this case is $20 let month

T is the time expended which in this case is x

Hope this helps!!