可汗学院
18.V=2.5(6.4?t)
Salma is filling her water jugs with spring water at the supermarket. The above equation gives the empty space in her jugs, V, in US gallons, after t minutes at a constant fill rate. How many minutes will it take to fill the jugs?
Correct answer: 6.4 Difficulty level: 2
19.T=0.25q+87
Manon's statistics professor puts a bonus question on every test, which adds 0.25 points to a student's overall grade at the end of the term. The above equation gives Manon's current overall grade, T, after taking into account q extra credit questions answered correctly. What does the 87 mean in this equation?
A.Manon must get an 87 or above to pass.
B.Manon's average is an 87 before adding the extra credit.
C.After adding in her extra credit, Manon’s average is an 87.
D.Manon's professor gave 87 opportunities for extra credit this term.
Correct answer: B Difficulty level: 2
20.T=10m+40
Tim decides to cook a steak. The interior temperature, T, of the steak, in degrees Fahrenheit(℉), after cooking for m minutes is given in the equation above. What does the 10 mean in the equation?
A.The interior temperature is 10℉when Tim starts cooking the steak.
B.The interior temperature of the steak increases by 10℉ for every minute it is cooked.
C.The interior temperature of the steak decreases by 10℉ for every minute it is cooked.
D.The interior temperature of the steak will increase a total of 10℉ while being cooked.
Correct answer: B Difficulty level: 2
21.5.5B+4R=28
The above equation models the cost if Amit picks B pounds of blueberries and R pounds of raspberries at a farm where blueberries cost $ 5.50 per pound and raspberries cost $ 4.00 per pound. According to the equation, how much does Amit spend in total on both types of berries?
A.$9.50
B.$22.00
C.$28.00
D.$56.00
Correct answer: C Difficulty level: 2