Question

5miles = 8km. How many km in 80miles?

Answer 1

128

Explanation:

Set this up as a proportion with miles on the top and km on the bottom:

`(mi)/(km):(5)/(8)`

If we want to know how many km are in 80 miles, we put the variable with the km stuff on the bottom and 80 on top and cross multiply to solve for the variable:

`(mi)/(km):(5)/(8)=(80)/(x)` so

5x = 640 and

x = 128

That means that 80 miles is equivalent to 128 km