Let t be the number of tolls they crossed.
Amount they spent at each toll = $1.75.
Amount they spent at gas station = $28.
Let C be the total amount they spent on gas and tolls.
If they crossed 1 toll, then
C = 28 + 1.75(1).
If they crossed 3 tolls, then,
C = 28 + 1.75(3)
If they crossed t tolls, then,
C = 28 + 1.75t
Here, the terms are 28 and 1.75t and the factors are 1.75 and t.
