you can always multiply by 1 without changing anything. So, since
5280 ft = 1 mi,
5280ft/1mi = 1mi/5280ft = 1
So, use the values of 1 which cancel the unwanted units. That way you never have to wonder whether to multiply or divide, and by what.
15mi/hr * 5280ft/mi * 1hr/3600s = (15*5280/3600) ft/s
Max Steel drives his 1969 Mustang 15 miles per hour. If there are 5280 feet in one mile and 60 seconds in one minute, how many feet can he go per second? I need help I don't understand.
4 answers
1 mile = 5 280 ft
1 h = 60 min = 60 ∙ 60 = 3 600 s
15 miles = 15 ∙ 5 280 = 79 200 ft
1 h = 3600 s
15 miles/ h = 15 mph = 15 ∙ 5 280 / 3 600 =
79 200 / 3 600 = 3 600 ∙ 22 / 3 600 = 22 ft / s
1 h = 60 min = 60 ∙ 60 = 3 600 s
15 miles = 15 ∙ 5 280 = 79 200 ft
1 h = 3600 s
15 miles/ h = 15 mph = 15 ∙ 5 280 / 3 600 =
79 200 / 3 600 = 3 600 ∙ 22 / 3 600 = 22 ft / s
So 220 ft/s?
Oh ok thank you!