word problem?

Question

Truck A, in point A, leaves the station at 8:00. Truck B,in point B, leaves the station at 8:10. Point A and B are 10 km apart. The trucks have same constant speed. Truck A and Truck B stopped at Point B and Point A, respectively, and waited for 30 mins before making their round trip. They met in a certain point at 9:20 while they were going back. What time did B returned to its station?

given are only those. :(

Answer 1

If they met at point X, truck B would have travelled 10+x Km in 40 mins travelling time. Truck A would have travelled [10 + (10-x)] Km in 50 mins travelling time. If you divide both distances by the respective travel times, you get the speed of each truck ...and since they are equal, you can equate the two. So (10+x)/40 = [10+(10-x)]/50. Solving this gives x=30/9 Km. So truck B travelled 10 + 30/9 = 120/9 Km in 40 mins, which is the same as 120/9 Km in 40/60 hr. Dividing the two you get that the speed of the trucks is 20 Km/h, so it take them 1 hr to do the round trip + 30 mins waiting time. So B gets back at 9:40

Answer 2

Well, I'm not great a word problems but I'll try to get you started.

It takes truck A 1 hour and 20 minutes to get to point X.
It takes truck B 1 hour and 10 minutes to get to point X.

If you take away the thirty minutes they spent waiting it looks like this:

truck A 50 minutes to point x
truck B 40 minutes to point x

I'm kinda lost from this point.

Perhaps if you could make a formula, you could figure it out. It's been a long time since I've had to do this sort of thing so it could take me some time to figure it out.

Answer 3

let TA = Truck A
let TB = Truck B
let t1 = transit time of TA from A to B
let t2 = transit time of TA from B to intersection point
let v = transit velocity

v*t2 = 10 - v*(t2-10)
t2 * (2v) = 10*(1+v)
t2 = 10*(1+v)/(2v)

t1 = 10 / v

t1 + t2 = 50

t1 + t2 =10/v + 10*(1+v)/(2v) = 50
50 = 10*(2 + 1+v) / (2v)
v*(100 - 10) = 30
v = 30/90 = 1/3 km/min

let tB be the round trip time for TB (including pause)
tB = (10 + 10) / v + 30 = 20 / (1/3) + 30 = 90 min = 1:30 hrs

B's arrival time at final destination is
8:10 + 1:30 = 9:40

Answer 4

9:40. Do you want the math?