Question

Dudley is biking. He wants to cover 40 miles. If he travels 30 miles every 2 hours, what is the equation of a line that models y, the number of miles he has left to travel, after biking x hours?

Answer 1

It is y = -15x + 40

Explanation:

Answer 2

Equation of a line that models y is:

y=40-15x

Explanation:

Dudley wants to cover 40 miles.

If he travels 30 miles every 2 hours

in 2 hours he covers 30 miles

i.e. 1 hour he covers 15 miles

Miles he is left with after 1 hour=40-15

Miles he is left with after 2 hours=40-15-15=40-15×2

Miles he is left with after x hours of biking=40-15x

If y represents the number of miles he has left to travel, after biking x hours

then, y=40-15x

Hence, equation of a line that models y is:

y=40-15x