Rate Problems Flashcards
Distance Rate formula
rate = distance/time
What are two rules when solving rate problems using matrix approach?
- units must be same
- time must be travel time but not time of the day
What is average rate?
total distance/ total time
What is the assumption about average rate?
Do no assume average rate is average of two rates
Converging rate questions rule
When two objects move toward each other, total distance travelled is equal to sum of distances of their individual distances regardless of how fast one is, where they meet
When both objects leave at the same time, what must be true?
their travel time is equal
When two objects leave at different time, what must be true?
object that leaves early has greater time travel than the other.
When one object travel faster than the another object, what must you do?
let slower object rate = r and faster object rate = r + x, where x = how much faster
first object is x% as fast as second object. convert their rates into variables
second object rate = r and first object rate = x/100(r)
What you can infer about round trip rate (a->b and b->a) questions?
distance from point a to b is equal to distance from point b to a
What you must assume about round trip rate questions?
rates are not same in both trips
What you must infer about distance in catch up rate questions?
When two objects start at the same point, their travel distance is equal when they catch up
Catch up rate formula =
t = delta d/ delta r
When you must use catch up rate formula?
When delta d is not equal to zero
What you must infer about time in catchup and pass rate questions?
both objects time is equal
