SAT I Math Problem

Discus: SAT/ACT Tests and Test Preparation: July 2004 Archive: SAT I Math Problem
 By Andrew1218 (Andrew1218) on Friday, July 09, 2004 - 08:35 pm: Edit

ok, I just did a test out of 10 reals i missed 2 questions, 1 was a dumb mistake and 1 i have no clue..this is the first SAT I problem i havent been able to atleast figure out after I spend a while on it and think about it. so here it is...

Ms. Clark drove from her home to the museum at an average speed of 40 mph and returned home along the same route at an average speed of 35 mph. If her total driving time for the trip was 2 hours, how many MINUTES did it take Ms. Clark to drive from her home to the museum?

this is really really annoying me that i cant do this problem, so i would really appreciate it if someone showed me how to do this.. muchas gracias

 By Joshjmgs (Joshjmgs) on Friday, July 09, 2004 - 10:31 pm: Edit

t1 = time there
t2 = time back
t1 + t2 = 120
t1 = 120 - t2

40 miles/hour * 60 minutes/1 hour =miles/minute
35 miles/hour * 60 minutes/1 hour =miles/minute

velocity*time = distance
Since she travels the same distance
(40*60)*(t1) = (35*60)*(t2)
Plug in for t1
(40)*(120 - t2) = 35*t2
4800 - 40t2 = 35t2
4800 = 75t2
t2 = 64 minutes
The t1, the time in which it took Ms. Clark to drive from her home to the museum is 120-64 = t1 = 56 minutes

 By Andrew1218 (Andrew1218) on Saturday, July 10, 2004 - 03:03 am: Edit

thanks a lot..that is actually a pretty hard problem for SAT I math