Rates

Question 1

Combined rates: bodies moving towards or away from each other; and moving in the same direction. Answer the combined rate:

(1) A and B move toward each other at 5mph and 6mph respectively
(2) Two cars move away from each other at 30mph and 45mph respectively
(3) x and y move in teh sae direction, with x behind y, x is moving at 8mph and y at 5mph

Answer 1

(1) they are decreasing distance between themselves at 11mph
(2) they increase distance between themselves at 75mph
(3) x and y decrease distance between themselves at 3mph

Question 2

Imagine someone travels at 4mph and then returns at 6mph. Is the average speed 5mph? (t/f)

Answer 2

FALSE af.

avg speed = total distance / total time

pick a random multiple of both. let’s say 12 mi is the one-way trek. Then it took 3h one way, and 2h on return

average speed: 24mi / 5h = 4.8

Question 3

Machine A can make 5 boxes /h, and Machine B, 12. Together, they do 17 b/h. If one worker is undoing the work of the other, subtract the rates. “Pool fills at 3g/m, but drains at 1g/m, then it fills at ___”

Answer 3

2g/m