What's the answer?? Please help

Question

A bike shop owner rents out bikes and scooters. The cost to rent a bike is $16 plus $9 per hour for each hour the bike is rented. The cost to rent a scooter is $30 plus $4 per hour for each hour the scooter is rented.

Which bike shop item costs has a greater rate of change? The rate that represents the cost of renting a bike or the rate that represents the cost of renting a scooter? Explain.

Answer 1

B = 16 + 9H

S = 30 +4H

the bike rental has a greater rate of change. 9>4. $9 per hour is greater than $4 per hour

for every additional hour, it costs more per hour for the bike than the scooter

the usual question for this type of problem is when is the total rental cost cheaper?

16+9H = 30+4H

5H = 14

H = 14/5 = 2.8 hours is when the costs are equal

for 3 hours or more the scooter is less expensive

for 2 hours or less, the bike is less expensive

if they charged by the minute, the costs would be equal at 2 hours and 48 minutes or 168 minutes