Final answer:
To find out when Marta's $15.00 off and 25% off coupons give the same value, solve the equation 0.25x = $15.00, which gives x = $60.00. Thus, the bill would need to be $60.00 for the two coupons to offer the same discount value.
Step-by-step explanation:
To determine how much a bill needs to be for Marta's two coupons to give the same value, we need to equate the flat discount to the percentage discount and solve for the bill amount. Let's use an equation where x represents the original bill amount.
For the $15.00 off coupon to equal a 25% discount, the equation is:
0.25x = $15.00
Dividing both sides by 0.25 to solve for x, we get:
x = $15.00 / 0.25
x = $60.00
Thus, the bill would have to be $60.00 for both coupons to offer the exact same discount, making the correct choice (c) $60.