Question

Sam is driving from Chicago to San Francisco, a distance of 2220 miles. He covers the first 192 miles in 4 hrs. At this rate, how long will the entire trip take?

Answer 1

We can set it up like this:

$\frac{192}{4} = \frac{2220}{x}$

This states that Sam can drive 192 miles in 4 hours and 2220 miles in x hours.  To solve, we can use cross-multiplication:

$192x = 2220*4 \\ 192x = 8880 \\ x = \frac{8880}{192} \\ x = 46.25$

It will take Sam 46.25 hours to drive the whole trip, or 46 hours and 15 minutes.