diep left alone for a bike ride at 8:00am traveling at 20mph . 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?
2007-04-30 13:19:04 · 4 answers · asked by K00LiSH [#1 Kings fan!] 5 in Science & Mathematics ➔ Mathematics
Since Mai rides twice as fast, she will only need to ride for half the time that Diep does. That means it will take her another half hour; after that time she will have been riding for 1/2 hour (20 miles) and Diep will have been riding for 1 hour (20 miles).
2007-04-30 13:23:30 · answer #1 · answered by Scarlet Manuka 7 · 0⤊ 0⤋
Since Diep got a 30 min headstart, when Mai starts, Diep would've already traveled 10 miles (20 mph * 0.5 hours). Let x be the amount of time(in hours) Mai has been riding.
This means that Mai has travelled 40x miles. Diep has travelled 20x miles plus the extra 10 mile headstart.
When the two distances are equal, Mai would have caught up.
40x = 20x + 10
20x = 10
x = 1/2 hour
2007-04-30 20:27:15 · answer #2 · answered by the redcuber 6 · 0⤊ 0⤋
20x=40x-10 (minus 10 because they left a half hour later)
10=20x
.5=x
so 1/2 an hour
2007-04-30 20:24:16 · answer #3 · answered by leo 6 · 0⤊ 0⤋
half an hour
2007-04-30 20:25:52 · answer #4 · answered by khalidah m 2 · 0⤊ 0⤋