How do you find the percent increase using proportions given 55 mph to 70 mph?

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Answer 1 · 2016-08-15T11:50:41

#27.27%#

The original starting speed of 55mph represents 100%, while the speed of 70mph is the speed increased by a certain percent

#55/100 = 70/x#

#55x = 70 xx100#

#x = (70 xx100)/55#

#x = 127.27#

The percent increase is therefore 127.27-100 = 27.27%

This can be checked by the method:

#("change")/("original") xx 100%#

#15/55 xx100% = 27.27%#