ASVAB CampRates and Unit Rates flashcards
8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.
Term · 1/8
What is a unit rate and how do you find it?
The amount of the first quantity for exactly one unit of the second; divide the first by the second. 450 gallons in 15 minutes is gallons per minute.
Formula · 2/8
What is the distance, rate and time formula with its rearrangements?
, , , where d is distance (miles), r is rate (miles per hour) and t is time (hours). Keep the units matched.
Common trap · 3/8
A car goes 40 mph for 30 minutes. How far does it travel?
20 miles. Convert minutes to hours first (30 minutes = 0.5 hour). Multiplying 40 by 30 gives 1,200, which is 60 times too large.
Strategy · 4/8
How do you decide which package is the better buy?
Compare the price per unit, not the sticker price. 6 bottles for 4.20 dollars is 0.70 dollar each; 10 for 6.50 dollars is 0.65 dollar each, so the bigger pack is cheaper per bottle.
Formula · 5/8
Two painters need 4 hours and 12 hours alone. How long together?
Add rates of job per hour: , so 3 hours. A team is always faster than its fastest member.
Rule · 6/8
An inlet adds 20 L/min and a leak loses 4 L/min. Time to gain 400 L?
Use the net rate: liters per minute, so minutes. Dividing by the inflow alone is the trap.
Rule · 7/8
In relative motion, when do you add speeds and when do you subtract?
Add when the objects move toward each other or apart in opposite directions; subtract when one follows the other in the same direction. Then time = gap divided by that combined speed.
Strategy · 8/8
How can units reveal a setup error in a rate problem?
Let units cancel like factors: miles per hour times hours leaves miles; miles divided by miles per hour leaves hours. A result in miles times hours, or hours per mile for a speed, means you mixed up multiply and divide.