If the car had traveled 20kmph faster than it actually did, the trip would have lasted 30minutes less. If the car went exactly 60km, what speed did it travel?
Here is my equation and I can't get to the right answer... Where am I making the mistake?
Rt-1/2R+20t -10 =60 ---> Rt-1/2R+20t=70
60-1/2R+20t=70 ---> -1/2R+20t=10 (t=60/R)
-1/2R+20(60/R)=10 ---> 1200/R-R/2=10 --> (2400-R^2)/2R=10
2400-R^2=20R ---> R^2 - 20R-2400=0
So R= 60... OA is 40.... what am I doing wrong?
2400 - R^2 = 20R
R^2 + 20R - 2400 = 0
(R + 60)(R - 40)=0
R = 40
I knew it was something so simple, but I just couldn't snuff it out.