Answer:
4 hours of rental
Step-by-step explanation:
y1 = 20 + 13.5x
y2 = 6 + 17x
20 + 13.5x = 6 + 17x
20 - 6 = 17x - 13.5x
14 = 3.5x
x = 4
Costs y1 and y2 are equal on renting for 4 hours
37% out of 87% equals to 42.5
D + q = 40
.10d +.25q= $7.75
d +q = 40
d =40-q
.10(40-q) +.25q= $7.75
4 - .10q + .25q =7.75
4 +.15q =7.75
4-4 +.15q =7.75-4
.15q= 3.75
.15q/.15 = 3.75/.15
q = 25
d =40-25
d = 15
Check
.10(15) +.25(25)= $7.75
1.5+6.25=7.75
7.75=7.75