jack runs 3miles in 27 minutes at this rate how long will it take him to run 10 miles
3 / 27 = 3 / ( 3 * 9 ) = 1 / 9
3 / 27 = 10 / x
1 / 9 = 10 / x Multiply both sides by 9
1 = 90 / x Multiply both sides by x
x = 90 min
OR
x = ( 10 miles / 3 miles ) * 27 min = ( 10 / 3 ) * 27 min = 270 min / 3 = 90 min