Rates Flashcards
If Rafa hits 163 severs in his first two hours of practice, how many more hours will it take him to hit 978 serves at the same rate?
** Your clue is in the question “how many MORE hours” **
Set up an average pie to help with the rate
163
2 x 81.5 then 978 - 163 = 815 then set up another rate pie
815
Time x 81.5 then you get Time = 10 which is your answer
Percent change = ?
Percent change = difference / original x 100
Car A is traveling at a constant speed of 55 miles per hour and Car B is traveling at a constant speed of 60 miles per hour. If Car A is already 35 miles ahead of Car B, how many hours will it take for Car B to overtake Car A?
At 7 hours, Car A will be at 420 miles and Car B will be at 420 miles. 7 hours is the answer. NOT 8.
What is the rate formula?
D = R x T
Distance = Rate x Time
Jack and Jill are walking in the same direction along a road and Jack is 30 steps behind Jill. If Jack walks at a constant speed of 40 steps per minute and Jill walks at a constant speed of 32 steps per minute and Jack’s steps are the same length as Jill’s, in how many minutes will Jack be 10 steps ahead of Jill?
If Jack and Jill are walking in the same direction along the same road, the speed at which Jack will overtake Jill can be found by subtracting the difference of their rates. Or in other words, Jack walks an additional 8 steps per minute.
Next find the total distance Jack needs to walk to be 10 steps ahead of Jill. He needs to fill the gap of 30 steps and then walk an additional 10 steps to be ahead, which = 40 steps.
Now use D = R x T formula
40 = 8 x T
So, t = 5
Hose 1 takes twice as long to completely fill a pool as Hose 2. If the two hoses can completely fill the pool in 6 hours when working together each at its own constant rate, how many hours are required for Hose 1 to completely fill the pool?
When you pick a number to solve this, what should it be a multiple of?
Answer = the number should be a multiple of 6. Here 36 works well, then solve, the final answer = 18.
Car A is traveling at a constant speed of 55 miles per hour. Car be is traveling at a constant speed of 60 miles per hour. If Car A is currently 35 miles ahead of Car B, how many hours will it take for Car B to overtake Car A?
D = R x T
First, do the rate trick, 60 miles per hour minus 55 miles per hour = in order to catch up, Car B must go 5 miles per hour faster. Then look at how many miles have to be completed to catch up which = 35 miles. So the distance you need to go is 35 miles = 5miles/ hour (rate) x Time. Therefore, time = 7 hours which is the answer.
