Question

Last week, your delivery runs took 7 hours 12 minutes on Monday, 6 hours 46 minutes on Wednesday, and 6 hours 53 minutes on Friday. What was your average time for a delivery run?

Answer 1

6 hours 57 minutes

Explanation:

1 hour = 60 minutes

On Monday delivery time = 7 hours 12 minutes

Change into minutes, 7 hours 12 minutes = 7×60+12 = 432 minutes

On Wednesday delivery time = 6 hours 46 minutes

Change into minutes, 6 hours 46 minutes = 6×60+46 = 406 minutes

On Friday delivery time = 6 hours 53 minutes

Change into minutes, 6 hours 53 minutes = 6×60+53 = 413 minutes

To find the average time for a delivery run.

`\text{Average}=\frac{\text{Sum of all data}}{\text{Number of data}}`

`\text{Average}=(432+406+413)/(3)`

`\text{Average}=(1251)/(3)`

`\text{Average}=417\text{ minutes}`

Now change 417 minutes to hour

60 minutes = 1 hour

417 minutes = 6 hours 57 minutes

Hence, the average time for a delivery run is 6 hours 57 minutes

Answer 2

`\boxed{\textbf{6:57}}`

Explanation:

`\text{Average time} = \frac{\text{total time}}{\text{number of runs}}`

1. Add the hours and minutes separately

`\begin{array}{rcr}7 &: & 12\\6 & : & 46\\6 & : & 53\\\mathbf{19} &:& \mathbf{111}\\\end{array}`

2. Calculate the average time

`\text{Average time} = \frac{19:111}{\text{3}}`

The hours do not divide evenly by 3.

(a) Convert the hours to a multiple of 3.

Subtract 1 h from the hours and add 60 min to the minutes

`\begin{array}{rcr}19 & : & 111\\- 1 & : & + 60\\\mathbf{18} & : & \mathbf{171}\\\end{array}`

Now, the hours are divisible by 3.

(b) Divide by three

Divide the hours and the minutes separately

`\text{Average time} = \frac{18:171}{\text{3}} = \mathbf{6:57}\\\\\text{The average time for a delivery run was $\boxed{\textbf{6:57}}$}`