At what time will John catch up with Mary?
2007-09-26 11:11:57 · 3 answers · asked by mztana820 1 in Science & Mathematics ➔ Mathematics
After 2 hours Mary has travelled 48 miles.
Relative speed of John to Mary = 24 mph
Thus can assume Mary at rest and John travelling at 24 mph.
John will take 2 hours to catch Mary.
Time = 1 pm
2007-09-30 07:19:37 · answer #1 · answered by Como 7 · 0⤊ 0⤋
Say they will meet-up T hours after 9 am.
At that time, Mary would have travelled 24 mph* T miles (distance = rate*time)
John would have trabelled 48 mph* (T-2) miles, since he had a late start of two hours.
So, 24T = 48(T-2), or
24 T = 48T - 96, gather like terms
96 = 48T - 24T, note sign changes
96 = 24T, divide by 24 so
T = 4, or 1:00 pm.
Check by figuring out how far each would have travelled.
2007-09-26 18:17:48 · answer #2 · answered by pbb1001 5 · 0⤊ 0⤋
do your own homework
2007-09-26 18:15:15 · answer #3 · answered by linz 4 · 1⤊ 0⤋