## Sunday, November 4, 2012

### Textbook pg.61 #21

Question:
21. Andrew drove his car 234 km from Dawson to Mayo in Yukon Territory in 3 h. Brian drove his truck along the same route at an average speed of 5 km/h greater than Andrew's average speed. How much less time did Brian take, to the nearest minute?

It says that Andrew drove 234km from dawson to Mayo in Yukon Territory in 3h, and Brian took the same root as Andrew with an average speed of 5 km/h.

We need to figure out Andrew's average speed by dividing his distance by the hour.

Since Brian's average speed is 5 km/h greater than Andrew's speed, we add Andrew's average speed by 5 km/h to get 83 km/h.

Now that we have Andrew's and Brian's average speed, we need to know find out how much less time did Brian take.
To find the time that Brian took, we divide the distance by the speed.

234 km = 2.819
83 km/h

We need to multiply 2.819 hours by 60 because there are 60 seconds in a minute. We would get the answer of 169 minutes
Convert 169 minutes to make 2 hours and 49 minutes

To find out how much less time Brian took, we subtract Andrew's and Brian's time.

3:00 hours - 2:49 = 11 minutes

It took Brian 11 minutes less than Andrew to get from Dawson to Mayo in Yukon Territory.