posted by Dawn on .
Please help me! I don't even know where to start :( my teacher took this question up on friday but i was sick, and we have a test tomorrow!
-Car A travels from Barrie to Subuiry at an average speed of 90km/h
-Car B travels from Subury to Barrie at an average speed of 80km/h
-Barrie and Subury are 300 km apart
(HINT: Recall that Distance=SpeedXTime. THink of the distance that each car is from ONE of the cicties when stetting up youre equations)
a) What does the point of intersection mean in this case?
b) If they left at exactly 9:35 am, at what time will they meet?
Say they travel for t hours
Car A goes 90 * t km
Car B goes 80 * t km
If car A goes distance d, then car B goes 300-d
d =90 t
80 t = 300 - d
80 t = 300 - 90 t
170 t = 300
t = 1.764 hours
1 hour and .764*60 minutes
= 1 hour and 45.882 minutes
call it 1 hour and 46 minutes although we could figure out the seconds
9:45 + 1 hr = 10:45
10:45 + 46 minutes = 11:00 + 31 minutes