Write and solve an eqn of ratios to determine the answer to this qu:
156 miles 4 gallons
-------------- = --------------
x 6 gallons
So (156)(6) = 4x, or 39(6) = x = 234 miles (answer)
Alternatively, determine the unit rate:
156 miles
-------------- = 39 mpg
4 gallons
Then 39 mpg times 6 gallons comes out to 234 miles.