Answer:
7500 revolutions
Step-by-step explanation:
1 rotation of his bicycle tires is equivalent to 1 circumference in linear distance.
circumference = π*diameter = π*20 = 62.8 in
If 1 foot is equivalent to 12 inches, then 62.8 in are equivalent to:
1 ft / x ft = 12 in / 62.8 in
x = 62.8/12 = 5.2 ft
If 5280 ft are equivalent to 1 mile, then 5.2 ft are equivalent to:
5280 ft / 5.2 ft = 1 mile / x mile
x = 5.2/5280 = 0.001 mile
So, when 1 revolution is made, 0.001 mile had been travelled. To compute the number of revolutions after 7.5 miles are travelled, the following proportion must be satisfied:
1 revolution / x revolutions = 0.001 mile / 7.5 miles
x = 7.5/0.001 = 7500 revolutions
