Answer:
A) 40
B) $ 15
Explanation:
A)An equation for the number of 30-day periods until the value of the gift cards will be equal
Let x be the number of time periods for which the gift card is not used, then
For the gift card $ 155 if it is not used for x periods, then the amount that will be lost is
155 - 3.50 x---------------------(1)
For the gift card $ 135 if it is not used for x periods, then the amount that will be lost is
135 - 3x---------------------- (2)
Now when both the amount lost is equal
solving the equation, we get
20 = 0.5x
x = 40Thus the value of gift cards will be equal for 40 ,30 day periods. B)The value of each card be when they have equal value The two cards will have equal value after 40 30 day periods, this denotes that at this time, the value of each card will be equal.Then substituting x = 40, we get when they have equal value, the value of each card will be $15