help me solve this question without algebra.=x
Lily is meeting a friend at a certain time. If she drives at 80km/h, she will be 1/3 hour late. If she drives at 60km/h, she will be 3/4 hour late. How long will the journey take if she drives at 90km/h?
Thanks! (:
Originally posted by wAt3v3r:help me solve this question without algebra.=x
Lily is meeting a friend at a certain time. If she drives at 80km/h, she will be 1/3 hour late. If she drives at 60km/h, she will be 3/4 hour late. How long will the journey take if she drives at 90km/h?
Thanks! (:
Hi,
as we know, Total Distance/Speed - amount of hours late = Original Planned Time
Thus, in the first case scenario ( Speed=80km/h ),
Total Distance/80 - 1/3 hour = Planned Time
And in the second scenario ( Speed=60km/h ),
Total Distance/80 - 3/4 hour = Planned Time
Putting the two equations together, we will have
Total Distance/80 - 1/3 hour = Total Distance/80 - 3/4 hour
Hence, Total Distance of journey = 100km.
If she drives at 90km/h, the journey will take 100/90 hours, which will be 1 hour 6 minutes and 40 seconds.
ok. thanks! (: