Question

Jose can read 7 pages of his book in 5 minutes. At this rate, how long will it take him to read the entire 175 page book?

Answer 1

125 minutes, or 2 hours and 5 minutes.

$\frac{5}7 = \frac{x}{175}$
cross multiply
5*175=7x
875=7x
$\frac{875}7=x$
125=x

Answer 2

Set up a proportion pages/pages= minutes/ minutes
7/175=5/x 
Note: x is the unkown variable or how long it will take him to read a 175 page book.
--Now do the math-- or cross multiply-- 
7(x)=175(5) 
reduce it down
7(x)=875
divide both sides by 7 in order to get variable x alone
x=125 
So it will take Jose 125 minutes to read the entire 175 page book.