SOLUTION: Diep left alone for a bike ride at 8:00 AM, traveling at 20 MPH. Half an hour later, Mai noticed that Diep had left her water bottle at home. If Mai rides 40 MPH, how long will it

Question 138925: Diep left alone for a bike ride at 8:00 AM, traveling at 20 MPH. Half an hour later, Mai noticed that Diep had left her water bottle at home. If Mai rides 40 MPH, how long will it take her to catch up to Diep?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Diep left alone for a bike ride at 8:00 AM, traveling at 20 MPH. Half an hour later, Mai noticed that Diep had left her water bottle at home. If Mai rides 40 MPH, how long will it take her to catch up to Diep?
:
We know that when M catches D, they will have traveled the same distance:
Make a simple Distance equation from this fact: (Dist = speed * time)
:
Let t = time (in hrs) for M to catch up with D
;
D started half hr earlier so his time:
(t+.5) = traveling time of D
:
M's dist = D's dist
40t = 20(t+.5)
:
40t = 20t + 10; some simple algebra
:
40t - 20t = 10
:
20t = 10
t =
t = .5 hr for M to catch up with D
:
:
Check solution by confirming they traveled the same distance:
D's time = 1hr
40*.5 = 20 mi
20*1 = 20 mi

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