Martina leaves home at 9 A.M., bicycling at a rate of 24 mi/h. Two hours later, John leaves, driving at the rate of 48 mi/h. At what time will John catch up with Martina?
2007-08-13 05:14:40 · 3 answers · asked by too_b2000 1 in Science & Mathematics ➔ Mathematics
If t=time in hours...then.
24t+48 (how fast Martina is going, plus the 48 miles she traveled in 2 hours.)
48t (how fast John is going.)
set equal to find out when they meet.
24t+48=48t
divide by 24.
t+2=2t
subtract t.
2=2t-t
simplify.
2=t
add 2 to the time when John leaves (11 AM) and you get 1 PM.
2007-08-13 05:23:29 · answer #1 · answered by Anonymous · 0⤊ 0⤋
John has left at 11:00 A.M
Let's see the distance both of them went at time t:
Martina rode 24(t - 9) miles
John drove 48(t - 11) miles
24(t - 9) = 48(t - 11)
24t - 9*24 = 48t - 48*11 // - 24t + 48*11
48*11 - 9*24 = 24t // divide by 24
2*11 - 9 = t
t=13 (13:00 is 1PM)
John will catch up with Martina at 1:00 PM
2007-08-13 12:23:36 · answer #2 · answered by Amit Y 5 · 0⤊ 0⤋
48 + 24t = 48t, so 48 = 24t, and t = 2.
They will meet at 1 pm.
2007-08-13 12:18:38 · answer #3 · answered by John V 6 · 1⤊ 0⤋