可汗学院
26.p=23+10(h-1)
People start waiting in the line for the release of the newest cell phone at 5 a.m. The equation below gives the number of people, P, in line between the hours, h, of 6 a.m. and 11 a.m., when the doors open. Assume that 6 a.m. is when time . What does the 23 mean in the equation above?
A.There are 23 people in line at 6 a.m.
B.After 10 hours, a total of 23 people will be in line.
C.Every hour between 5 a.m. and 11 a.m., 23 more people get in line.
D.Every hour between 6 a.m. and 11 a.m., 23 more people get in line.
Correct answer: A Difficulty level: 3
27.S=40,000+500c
Caden started a new job selling dental chairs. He earns a base salary plus a commission for every chair he sells. The equation above gives Caden's annual salary, S, in dollars, after selling c dental chairs. Based on the equation above, what is Caden's base salary?
A.$39,500
B.$40,000
C.$40,500
D.$50,000
Correct answer: B Difficulty level: 2
28.Anthropologists have noticed that they can predict the height of a human being based on the length of their femur. The relationship between the person’s height, H, in centimeters, and length of the femur, f, in centimeters, can be modeled by the equation below.
H=2.72f+42.12
One anthropologist found the femurs of two different people. One femur measured 22 centimeters and the other femur measured 23 centimeters. What is the difference in their heights?
A.1 centimeter
B.2.72 centimeters
C.27.2 centimeters
D.42.12 centimeters
Correct answer: B Difficulty level: 3
29.d=1.06(212-t)
A spacecraft heading for Pluto will take pictures of several other planets on its way. The above equation gives the distance, d, in millions of kilometers, of the craft from its first photo opportunity with Mars in terms of the time, t, in days. What is the meaning of the 212 in this equation?
A.The spacecraft travels 212 kilometers per day.
B.It will take the spacecraft 212 days to reach the Mars photo opportunity.
C.The spacecraft begins its journey 212 kilometers from the Mars photo opportunity.
D.After 212 days, the spacecraft will be within 1.06 kilometers of the Mars photo opportunity.
Correct answer: B Difficulty level: 3
30.35A+28P=250
Vera is hiring entertainers for her charity event. She is using the equation above to determine the number of hours, A and P, to hire a caricature artist and a face painter for, respectively, with a total budgeted cost of $250. The caricature artist charges $35 per hour and the face painter charges $ 28 per hour. What is the meaning of the 35A in this equation?
A.The caricature artist charges 35A dollars per hour.
B.The caricature artist works for a minimum of 35A hours in a week.
C.For the first 35 hours each week, the caricature artist makes A dollars.
D.The caricature artist charges a total of 35A dollars for A hours worked.
Correct answer: D Difficulty level: 3