Question

The capacities of two trucks are 3 tons and 4 tons respectively. If the smaller truck makes 18 more trips than the larger, it can deliver 12 more tons of freight than the larger. How many trips does each truck make? Let x represent the number of trips that the larger truck makes. Which of the following equations could be used to solve the problem?
4x - 3(x + 18) = 12
3(x + 18) - 4x = 12
3x - 4(x + 18) = 12

Answer 1

Let's assume

x represent the number of trips that the larger truck makes

so, we are given

If the smaller truck makes 18 more trips than the larger

so,

number of trips for larger truck =x

number of trips for smaller  truck =x+18

The capacities of two trucks are 3 tons and 4 tons respectively

so, capacity of smaller truck per trip =3 tons / trip

total ton carried by smaller truck = (number of trips for smaller  truck)*(capacity of smaller truck per trip)

now, we can plug values

total ton carried by smaller truck =3*(x+18)

total ton carried by larger truck = (number of trips for larger  truck)*(capacity of larger truck per trip)

total ton carried by larger truck =4x

it can deliver 12 more tons of freight than the larger

so, we get

$3(x+18)=4x+12$

we can move 4x on left side

we get

$3(x+18)-4x=12$...............Answer