Jacob rode his bike 2 miles in 20 minutes. Denise rode her bike 15 miles in 2 hours. Who went faster?

Question

my math teacher made this problem really confusing for me to understand so I barley know how to solve these types of problems

Answer 1

First, Stephanie, you need to get everything in the same units then compare them. Because Jacob's time is in minutes, let's use that as our time units. Both distances are in miles, so there is nothing to do here. Because 1 hour is 60 mins, we see that Denise rode her bike:   15miles/2hrs

                                         15miles/(2hrs x 60mins/hr)

                                         15miles/120mins

                                         .125miles/min

Jacob rode his bike:            2miles/20mins

                                        .100miles/min

Comparing the two you can see that Denise rode her bike faster at .125miles/min than Jacob did at .100miles/min!

Answer 2

Hi, Stephanie. 

Let me try to help you.

Okay, so in order to compare their speeds, they need to be expressed in the same terms.

 

So, Jacob rode his bike 2 miles in 20 minutes. We can express his speed in mph.

2mi/20min x 60min/hour = 120/20 = 6 mi/hr

 

Now, Denise rode her bike 15mi/2hr. To change this in mi/hr:

15mi/2hr = Xmi/hr

15 mi = 2X

7.5 mi = X

X = 7.5 mi/hr

So, Denise rode 7 1/2 mph

and Jacob rode 6 mph

 

 

Answer 3

2 hours = 120 minutes

Jacob - 2 miles/20 minutes = 1 mile/10 minutes

Denise - 15 miles/120 minutes = 1 mile/8 minutes

Denise went faster.