Question 160056
Mary is running to school. She leaves home at 7:00 am trotting at a speed of 12
 mph. Her little lamb leaves home at 7:15 am running after her at a speed of 17
 mph. What time of the day will the lamb catch Mary? Round your answer to the
 nearest minute.
:
Let t = Mary's travel time in hrs when lamb catches her
Convert 15 min to hrs 15/60 = .25 hrs
(t-.25) = travel time of lamb
:
When lamb catches Mary, they will have traveled the same distance
Write a distance equation using this fact;
Dist = speed * time
:
lamb's dist = Mary's dist
17(t-.25) = 12t
:
17t - 4.25 = 12t
:
17t - 12t = +4.25
:
5t = 4.25
t = {{{4.25/5}}}
t = .85 hrs 
Convert this to minutes: .85 * 60 = 51 min
:
Lamb catches Mary at 7:51 am
:
:
Check solution by ensuring they traveled the same dist: 
lambs time .85 - .25 = .6 hrs
17*.6 = 10.2 mi
12*.85 = 10.2 mi