## anonymous 3 years ago In the morning, Alan drove 100 miles at the rate of 60 miles per hour; in the afternoon, he drove another 100 miles at the rate of 40 miles per hour. What was his average rate of speed, in miles per hour, for the day?

1. anonymous

k...

2. anonymous

d=100

3. anonymous

anything?

4. anonymous

ahh

5. anonymous

60+40/2=50

6. anonymous

derp

7. anonymous

C.

8. anonymous

no

9. anonymous

B.

10. anonymous

48

11. anonymous

nope

12. anonymous

that'swrong

13. anonymous

it's 48

14. anonymous

heck no

15. anonymous

oh i mean heck no to 50

16. anonymous

average speed is not the average of the speeds

17. anonymous

oh man, you are a guru

18. anonymous

you are even higher than DA PANIC!!!!!!

19. anonymous

Oh, sorry...just been a while since I've done these...

20. anonymous

figure out how long it took to get there, then figure out how long it took to get back that is the total time divide the total distance (200 miles ) by the total time to get the average speed

21. anonymous

2.5+1.666666667

22. anonymous

divided by 200

23. anonymous

equal 48

24. anonymous

that it?

25. anonymous

200/4.166666667?

26. anonymous

=48

27. anonymous

100/60=5/3

28. anonymous

100/40=2.5

29. anonymous

time going it $$\frac{100}{60}$$ time returning is $$\frac{100}{40}$$ total time is $\frac{100}{60}+\frac{100}{40}=\frac{25}{6}$ and $200\div \frac{25}{6}=200\times \frac{6}{25}=8\times 6=48$ as luisz said

30. anonymous

5/2+5/3=15/6+10/6=25/6

31. anonymous

200 divided by 25/6=48

32. anonymous

ty

33. anonymous

you nothing about truth tables, guru?

34. anonymous

now redo the problem replacing 100 by $$m$$ and see that the answer is still 48 mph

35. anonymous

by friend, aripotta needs help with them?

36. anonymous

yes, we can do them

37. anonymous

38. anonymous

its not me who needs help with them

39. anonymous

its aripotta

40. anonymous

I'm posting a different problem