Question

A chemistry teacher is able to grade chemistry labs at a rate of 5 labs for every 3 minutes. They need to grade 165 labs how many hours will it take?​

Answer 1

1.65hr

Step-by-step explanation:

Given parameters:

Number of labs = 5 labs

Time taken = 3 minutes

Unknown:

Time taken in hours to grade 165 labs = ?

Solution:

Let us find the rate of the teacher;

Rate =
`(number of labs)/(time)`

Insert the parameters and solve;

Rate =
`(5)/(3)` = 1.67labs/min

Now;

Time to grade 165 labs =
`(number of labs)/(rate)`

Time to grade 165 labs =
`(165)/(1.67)` = 98.8min

Since;

60min = 1hr

98.8min =
`(98.8)/(60)` = 1.65hr