Question 791346: Hi everyone! I'm having problems with a couple of problems. If anyone could help me I would appreciate it! The first question says "Working alone, Imani can pick 40 bushels of apples in 12 hours. José can pick the same amount in 8 hours. If they worked together how long would it take them?"
The second reads "A diesel train left Berlin and traveled toward Las Vegas at an average speed of 75 mph. A cattle train left 7 hours later and traveled in the opposite direction with an average speed of 50 mph. How long does the cattle train need to travel before the trains are 1,900 miles apart?"
I tried a system of equations for the first question, but it looks really bad. The second I have no clue how to even start it. If anyone could help I would love it! Thank you!
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
If A can do a job in x time periods, then A can do  of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do  of the job in 1 time period.
So, working together, they can do
of the job in 1 time period.
Therefore, they can do the whole job in:
time periods.
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The first train has a 7 hour head start. So how far did it go in those 7 hours a t 75 miles per hour? Subtract that amount from 1900 miles. After that, the rate at which they are moving apart, since they are going in opposite directions, is the sum of the two trains' speeds. Add the two speeds and divide into the remaining distance you just calculated. You can express it as a number with a decimal fraction, or a mixed number, or as hours and minutes. Hint if you want to do hours and minutes: One-fifth of an hour is 12 minutes.
John
Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
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