Isabel purchased a prepaid phone card for 25$. Long distance calls cost 18 cents a minute using this card. Isabel used her card only once to make a long distance call. If the remaining credit on her card is $22.48 , how many minutes did her call last?

4a. is 3 miles every hour

4b. is 1/3 of an hour per mile

step-by-step explanation:

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)