Sophia’s school took a field trip. a total of 21 vehicles were needed for the trip. some students the bus, and some students car-pooled. there were 30 people on each bus and 4 people in each car. 318 people altogether attended the trip. how many buses and cars were needed for the trip?

the answer would be c:   ax + b = ax + c

step-by-step explanation:

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have