SOLUTION: At 9:00 a.m. a truck leaves the truck yard and travels west at a rate of 50 mi/hr. Two hours later, a second truck leaves along the same route, travelling at 75 mi/hr. When will

Question 81960: At 9:00 a.m. a truck leaves the truck yard and travels west at a rate of 50 mi/hr. Two hours later, a second truck leaves along the same route, travelling at 75 mi/hr. When will the second truck catch up to the first?
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
let t=time (in hours) after truck #2 leaves until it catches truck #1
distance(d)=rate(r)times time(t)or d=rt; t=d/r and r=d/t
When truck #2 leaves at 11:00am, truck #1 has already travelled (50 mph)(2 hrs)=100 mi
distance truck #1 travels =100+50t
distance truck #2 travels=75t
Now we know that when the distance truck #1 travels equals the distance truck #2 travels, then truck #2 will have caught up with truck #1. So:
100+50t=75t subtract 50t from both sides
100+50t-50t=75t-50t collect like terms
25t=100
t=4 hrs --------------time it takes truck #2 to catch truck #1
11:00am plus 4 hrs=3:00pm----------time when truck #2 catches up with truck #1
CK
truck #1 travels 100+4(50)=300mi
truck #2 travels 4(75)=300mi
Hope this helps----ptaylor

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