Respuesta :
Answer: it will take twenty 30-day periods until the value of the gift cards will be equal.
The value of each card be when they have equal value is $10
Step-by-step explanation:
Let x represent the number of 30-day periods until the value of the gift cards will be equal.
Tavon has a gift card for $90 that loses $4 for each 30-day period it is not used. This means that x 30-day periods, the amount left would be
90 - 4x
He has another gift card for $ 80 that loses $ 3.50 for each 30-day period it is not used. This means that x 30-day periods, the amount left would be
80 - 3.5x
For the amounts left in each card to be the same, the number of periods would be
90 - 4x = 80 - 3.5x
90 - 80 = - 3.5x + 4x
10 = 0.5x
x = 10/0.5
x = 20
The value of each card be when they have equal value is
90 - 4 × 20 = 90 - 80
= $10
