1. The distance you travel varies directly with the amount of gas you use. You can travel 300 miles on 12 gallons of gas.

Write a direct variation equation in the form y = kx

2. How many gallons of gas will it take to travel 750 miles?

3. If gas costs $3.75 per gallon, how much will it cost in gas to go on your trip?

1.

y = distance traveled

x = gallons of gas used

k = slope of the graph between distance traveled and gallons of gas used

slope is given as

k = 300 miles / 12 gallons

k = 25 miles/gallon

so the equation can be written as

y = 25 x

2.

given : y = 750 miles

using the equation

y = 25 x

inserting the values

750 = 25 x

x = 30 gallons

3.

c = cost per gallon = $3.75

c = total cost

Total cost is given as

Total cost = Cost per gallon x number of gallons

C = c x

C = $3.75 (30)

C = $112.5