1. 2
Variation Real World

2. Using Direct Variation to solve word problems
A car uses 8 gallons of gasoline to travel 290 miles. How much gasoline will the car use to travel 400 miles?
Step One: Find points in table
Step Three: Use the equation
to find the unknown.
400 =36.25x
or x = 11.03
Step Two: Find the constant variation and equation:
k = y/x or k = 290/8 or 36.25
y = x

3. Using Direct Variation to solve word problems
Julio wages vary directly as the number of hours that he works. If his wages for 5 hours are $29.75, how much will they be for 30 hours
Step One: Find points in table.
Step Three: Use the equation
to find the unknown. y=kx
y=5.95(30) or Y=178.50
Step Two: Find the constant variation.
k = y/x or k = 29.75/5 = 5.95

4. #3 Solve the problem using direct variation.
The Weight (V) of an object on Venus varies directly as its weight (E) on Earth. A person weighing 120 lb on Earth would weigh 106 lb on Venus. How much would a person weighing 150 lb on Earth weigh on Venus?

5. #3 Solve the problem using direct variation.

6. #4 Solve the problem using inverse variation.
The time (t) required to drive a fixed distance varies inversely as the speed (r). It takes 5 hours at 60 km/h to drive a fixed distance. How long would it take to drive the same distance at 40 km/h?

7. #4 Solve the problem using direct variation.

8. #5 Solve the problem using combined variation.
Find an equation of combined variation where A varies directly as b and inversely as c. One set of values is A = 4, b = 12, and c = 9. Find A when b = 7 and c = 3.

9. #5 Solve the problem using combined variation.

10. #6 Solve the problem using variation.
The interest earned at Whole World Savings & Loan varies jointly as the amount deposited in the bank and the time elapsed since the deposit. If a $500 deposit earns $120 interest after 3 years, how much does an $800 deposit earn after 5 years?

11. #6 Solve the problem using variation.