Answer:
i dont under stand but i will just ask for help to my father
Step-by-step explanation:
i dont wnow the answer!???
Life expectancy of dollar bill = d
life expectancy of coin = c
d = 1/20 c
substitute value in for c (30)
d = 1/20 * 30
d = 30/20
d = 1.5
life expectancy of a dollar bill = 1.5 years
1.50 x R, R being the rides a visitor rides.
(Not 100% sure.)