1. anonymous

It took Jimena 89 minutes to run a 15-kilometer race last weekend. If you know that 1 kilometer equals 0.621 mile, how many minutes did it take Jimena to run 1 mile during the race? Round your answer to the nearest hundredth. 3.68 minutes 9.55 minutes 9.88 minutes 24.15 minutes

2. MichaelAlex292

First, you would need to know how many minutes it took her to run 1 kilometer. This would be set up in a proportion: $\frac{ 15 }{ 89 } = \frac{ 1 }{ x }$ Solve for x to find how many kilometers she ran in 1 minute. Then transfer it to minutes per mile. Do you know how to do that?

3. anonymous

u would cross multiply?

4. anonymous

okay so jimena's rate is 15 km/ 89 minutes convert this to 0.16853932584 km/ min which is equal to 0.16853932584(.621) miles/min set that [rate] equal to d/t so 0.16853932584(.621)=d [1 mile]/t solve for t

5. MichaelAlex292

To solve for x, yep

6. anonymous

I am sorry, but I don't know how to do that... could you help?

7. MichaelAlex292

To solve proportions, you cross-multiply by multiplying the terms that are diagonal to each other.

8. MichaelAlex292

So what would that be?

9. anonymous

89/15x?

10. MichaelAlex292

Yes! Now solve for x

She takes 89 min to cover (15×0.62)miles So for 9 miles time is 89min. For 1mile time taken is 89/9minutes =9.88min. (Approximately)

12. anonymous

5.9333333

13. MichaelAlex292

Yep, now multiply it by the conversion of km to miles to find the answer (Hint: Multiply it by 0.621)

14. anonymous

9.88?? (rounded)

15. MichaelAlex292

Hold on, I screwed up. You have to convert the 15 km into miles using the conversion given.

16. MichaelAlex292

Do you know how to do that?

17. MichaelAlex292

Once you find how many miles is in 15km, you set up the same proportion we did earlier, except swap the 15 with the new value that you get

18. MichaelAlex292

Then solve for x

19. anonymous

so what do i end up with? 9.88 is not the answer. @MichaelAlex292

20. MichaelAlex292

Its not 9.88, its actually 9.55. Sorry I screwed up :l

21. MichaelAlex292

Look above

22. anonymous

its alright... thanks!

23. MichaelAlex292

No problem :)