# Calculating the IntersectionWatch

#1
Hi everyone,

Can anyone help me out with calculating the intersection point of two vehicles travelling between two cities at different speeds, one setting off 30 minutes later than the other?

Thanks!!!
0
4 years ago
#2
post a photo of the problem
0
#3
(Original post by TeeEm)
post a photo of the problem
0
4 years ago
#4
(Original post by tommmyd)
speed of first car is 80 km/h
can you find the speed of the other car?
0
#5
(Original post by TeeEm)
speed of first car is 80 km/h
can you find the speed of the other car?
75km/h
0
4 years ago
#6
(Original post by tommmyd)
75km/h
sorry on the phone

correct.

next after 15 minutes A would have covered 20 km.
so by the time B starts the two cars will be 80 km apart...

Are you following so far?
Can you see what to do next?
0
#7
(Original post by TeeEm)
sorry on the phone

correct.

next after 15 minutes A would have covered 20 km.
so by the time B starts the two cars will be 80 km apart...

Are you following so far?
Can you see what to do next?

Thank you... I understand that but I am not sure what to do next.
0
4 years ago
#8
(Original post by tommmyd)
Thank you... I understand that but I am not sure what to do next.
Car A has speed 80
Car B has speed 75 (you correctly found this)

at 10.15 the cars are 80 km apart and moving towards each other ....

so every hour that goes by, the distance between them is "eaten" at the rate of (75 +80)= 155 km.

can you see what to do next?
0
#9
(Original post by TeeEm)
Car A has speed 80
Car B has speed 75 (you correctly found this)

at 10.15 the cars are 80 km apart and moving towards each other ....

so every hour that goes by, the distance between them is "eaten" at the rate of (75 +80)= 155 km.

can you see what to do next?
So in 30 minutes time the cars will be 77.5km closer to each other (2.5km apart)?
0
4 years ago
#10
(Original post by tommmyd)
So in 30 minutes time the cars will be 77.5km closer to each other (2.5km apart)?

do the right arithmetical operation and you will find the time (it is not exact)

then use it to find the distance from A (do not forget to add the 20 km)
0
#11
(Original post by TeeEm)

do the right arithmetical operation and you will find the time (it is not exact)

then use it to find the distance from A (do not forget to add the 20 km)
Am I right in thinking the cars will cross at about 10:46?
0
4 years ago
#12
(Original post by tommmyd)
Am I right in thinking the cars will cross at about 10:46?
30 min and 58 seconds after 10.15 when I did my calculations.

hope you followed it

PS what course is this problem for?
0
#13
(Original post by TeeEm)
30 min and 58 seconds after 10.15 when I did my calculations.

hope you followed it

PS what course is this problem for?
MST124 an Open module.

Thanks a lot!!!
0
4 years ago
#14
(Original post by tommmyd)
MST124 an Open module.

Thanks a lot!!!
all good
0
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