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Comment on Devi and Mark
Hello Brent, I have a doubt
Since Mark's speed is 15 mph
Since Mark's speed is 15 mph greater than Devi's speed, the gap between them keeps SHRINKING (at a rate of 15 miles per hour) until Mark catches up to Devi (once Mark passes Devi, then the gap between them will start to expand).
By the time Mark starts driving, the GAP between them is 12 miles.
So, to calculate the time until the gap = 0 miles (i.e., Mark catches up to Devi), we need distance/rate
Here, the distance = the initial gap (12 miles)
So, time = (12 miles)/(15 miles per hour)
Does that help?
Cheers,
Brent
using substitution we can
The distance traveled by Devi for 1 hr is 36 miles so at 2:00 Devi would have traveled 36 miles.
As Mark started 20 mins late, so at 2:00 Mark would have traveled 34 miles. (using cross multiplication Distance traveled for 40 mins = 51*40/60)
So Now we know answer must be greater we can eliminate
A and B and check for other options.
Now for 8 mins Devi would have traveled 4.8 (36*8/60) miles and Mark would have traveled 6.8 miles.(51*8/60)
So 36+4.8 = 34+6.8
and they meet at 2:08 PM
That works too!
That works too!
Would you plz explain how we
thanks
We know that the time it
We know that the time it takes for Mark to reach Devi = 4/5 hours.
This is the same as saying 4/5 of an hour.
This is the same as saying 4/5 of 60 minutes
4/5 of 60 = (4/5)(60) = 48
Cheers,
Brent