To get a fraction into the simplest form you need to find a common multiple that could divide into both the numerator and the denominator. Then it will decrease.
The answer is 208. The equation to get this is m=29g-140 where m is miles and g is the gallons. Plug 12 in for g and solve for m. 29 * 12 = 348, 348-140 = 208. Therefore, m=208.
