SOLUTION: Hi is it possible to have the formula to work out the following John drives from town A to town B at 90kmh for T Hours Jenny drives the same journey at 70kmh. she travels for 1

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Question 936885: Hi is it possible to have the formula to work out the following
John drives from town A to town B at 90kmh for T Hours
Jenny drives the same journey at 70kmh. she travels for 1 hour longer than John
How long did John drive for.
Assume constant speeds
I found the answer by drawing it out, which is 3.5 hours assuming I am correct, but there must be a mathematical formula for doing this correctly
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
John drives from town A to town B at 90kmh for T Hours
Jenny drives the same journey at 70kmh. she travels for 1 hour longer than John
How long did John drive for.
Assume constant speeds
The distance from A to B is 90T
Jenny time = 90 T/70
Jenny's time - john's time = 1
t=d/r
90T/70 -T = 1
90T-70T =70
20T=70
T= 70/20
T= 7/2
T=3.5 hours