A bus is traveling at 50 mph. If the rate of speed increases 3 mph each hour, how long will it be before the bus is traveling at a rate of 80 mph?

A. 9 hours
B. 10 hours
C. 11 hours
D. 12 hours

B. 10 hours

Step-by-step explanation:

Since the bus is already traveling 50mph and we need to figure out how long it will be until it is traveling 80mph we need to figure out the difference,

80-50 = 30

We need to figure out how long it will take for the bus to go 30 more mph. Since it increases 3mph every hour, if we divide the 30 by 3 we will figure out how long it will be until the bus is going 30 more mph (total of 80mph) and we will have our awnser

30÷3=10

It will take 10 hours before the bus goes 80 mph

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b