Kathy has a more cycle with a 4 gallon gas tank. On average, she can travel 60 miles per gallon.

Question

if M yes the number of miles driven since the last fill up, what formula can she use to find out how much gas is in left in the gas tank.

how did you decide how to use or not use the value for in the formula.

how did you decide how to use or not use the value 60 in the formula

if Kathy has driven 100 miles since she filled the tank, how much gas is left in the tank.

The distance from Dallas to Houston is 246 miles. Will she need to fill up on that trip.

Answer 1

a full tank will let her go, on average 4 x 60 = 240 miles

If she has traveled M miles then she can only go 240-M further miles

divide 240-M by 60 to see the remaining gallons in her tank

Gallons left = (240-M)/60 = 4 - M/60

If she's gone 100 miles then she has left 4-100/60 = 4-10/6 = 4-5/3 = 2 1/3 gallons left

she used up 1 2/3 gallons 4 minus 1 2/3 leaves 2 1/3 gallons

To go 246 miles would use up all 4 gallons after completing 4x60=240 miles. She would have to

get more gas to go the remaining 6 miles

Or using the formula,

Gallons left = 4 -246/60 = 4 - 4.1 = negative .1 gallon. She needs to get 1/10 of a gallon more to finish 246 miles.