Rational Equations

Question

During the winter Olympics, a downhill skier had to complete two qualifying heats to make it to the metal round. She finished her first run in 2 minutes and her second run in 3 minutes. Both runs took place on a course that was 4.3 km long. What was her average speed? Write answer as a whole number or as a decimal rounded to the nearest 10th. Show all work.

Answer 1

Hi Jacob.

Using our basic formula for Distance, D=RT we can combine the 2 runs to determine her average speed. Both runs covered 4.3k, so her total distance is 8.6. Her runs were 2 minutes and 3 minutes respectively which add up to 5 minutes.

Plug those into the Distance formula and we can solve for Rate. 8.6 = R(5).

Divide both sides by 5 to isolate the variable: 8.6/5=R(5)/5

Now we have the Rate in Kilometers per minute: 1.72=R(kpm)

To convert to Kilometers per hour multiply by 60: 103.2=R(kph)

Hope this helps.

Have a good night and stay safe.

michael.russell.10

Answer 2

Total distance/total time

8.6 km/5 min = 1.72 km/min

1.72 km/min x 60 min/hr = 103.2 km/hr