Exercise 21. When the speed limit was 55 mph, Bob could cover 400 miles in a day's driving. After the speed limit went up to 70 mph, how far would he go in an equivalent
day's driving? What assumptions are you making? Is it necessary to calculate the time
he spent driving?

ab will be equal to

17 1/3

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