Question

Melanie observes a marble travel along a horizontal path at a constant rate. The marble travels 1/30 of the length of the path in 2 1/4 seconds. At that rate, how many seconds does it take the object to travel the full length?

Answer 1

Answer: 67.5 seconds

Explanation:

The marble is traveling at a speed of 1/30 length units per 2.25 seconds.

Use direct proportion to find out the amount of time it would take to cover the whole length:

1/30            :          2.25 seconds

1                  :                  x

1/30 x = 2.25 seconds

x = 2.25 ÷ 1/30

x = 2.25 * 30/1

x = 67.5 seconds

67.5 seconds is 1 mins and 7¹/₂ seconds.