Difficult# Gas Mileage

SATMAT-IEKKJX

A car, which is able to travel $ m $ miles per gallon, has a gas tank which holds $ G $ gallons of gas.The car started a $200$ mile trip with a full tank of gas. After the trip, the gas tank was$ \frac { 3 }{ 8 } $ full.The equation: $T = G - \frac { 200 }{ m } $ represents the total amount of gas left in the tank after the trip.Which of the following is the value of $ G $ in gallons? (Calculator)