Find meeting time, given distance, and cycling rates.

sandyk109

New member
Joined
May 7, 2007
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15
At 9:30 a.m. Andrew left Exter for Portsmouth, cycling at 12 mi/h. At 10:00 a.m. Stacy left Portsmouth for Exetr, cycling at 16 mi/h. The distance from Exeter to Portsmouth is 20 mi. Find the time when they met.
 

skeeter

Senior Member
Joined
Dec 15, 2005
Messages
2,396
let t = time measured starting at 10:00 am when they meet

sum of the distance that both travel = 20

since rate*time = distance ...

16t + 12(t + .5) = 20

solve for t, then add the result to 10:00 am to find the time they meet.
 

Denis

Senior Member
Joined
Feb 17, 2004
Messages
1,465
Sandy, this is another (quicker) way to "get" answer:

when Stacy leaves, Andy has travelled 6 miles (1/2 hour @ 12 mph);
so distance left at that point = 20 - 6 = 14 miles;
this 14 miles is covered at combined speed of 12 + 16 = 28 mph;
so time to cover that = 14 / 28 = 1/2 hour;
so time of meeting = 10 + 1/2 = 10:30.
 
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