可汗学院数学题目-24Ratios,ratesandproportions

LEVEL 3

1.Playing tennis Playing squash

Energy

expenditure

rate 1,594kJ

ℎ

2,726

kJ

ℎ

Oxygen

consumption

rate 77L

ℎ

130

L

ℎ

Fat burning rate 49 g

ℎ

r

The table above lists average expenditure rates of playing tennis vs. playing squash based on a body weight of 55 kilograms. The ratio of each value in the tennis column to the corresponding value in the squash column is about the same throughout the table. Which of the following is closest to the fat burning rate r of squash?

A.27g ℎ

B.29g ℎ

C.83g ℎ

D.85g ℎ

Correct answer: C

2.Lea’s car travels an average of 30 miles per gallon of gas. If she spent $20.70 on

gas for a 172.5 mile trip, what was the approximate cost of gas in dollars per gallon?

A.$1.45 per gallon

B.$3.40 per gallon

C.$3.60 per gallon

D.$5.75 per gallon

Correct answer: C

3.Kavitha and Andrei are truck drivers for the Delightful Delivery Company,

which services cities W, T, and Q.

The distance from city W to city T is 48.5 miles.

The distance from city T to city Q is 20 miles.

The distance from city Q to city W is 36 miles.

If Kavitha's truck and Andrei's truck travel at the same speed, and it takes

Andrei 91 minutes to go from city W to city T, about how much time will it take Kavitha to travel from city W to city Q?

A.19 minutes

B.38 minutes

C.68 minutes

D.123 minutes

Correct answer: C

4.Yasemin is using a sugar cookie recipe with a flour to sugar ratio of 11:6. To

make one batch of cookies, 2.75 cups of flour are needed. If Yasemin would like to triple the recipe, which of the following best approximates how much sugar she will need?

B.** cups

5 cups

C.15 cups

Correct answer: B

5. A certain high school geometry class is made up of freshmen and sophomores.

The ratio of freshmen to sophomores in that class is 3:4. If there

are 12 sophomores in the class, what is the total number of students in the class?

A.9

B.16

C.21

D.28

Correct answer: C

1.The musical interval between two sounds is called an "octave" if the ratio of the

sounds' frequencies is 2:1. The following table shows the names of the musical intervals between two sounds based on the ratios of the two sounds' frequencies. Name of the musical interval Ratio of two sound frequencies

Major third 4:5

Perfect fourth 3:4

Perfect fifth 2:3

Major sixth 3:5

If a sound is played with a frequency of 480 Hz, and a second sound is played with a frequency of 800 Hz, what is the name of the musical interval between the two sounds?

A.Major third

B.Perfect fourth

C.Perfect fifth

D.Major sixth

Correct answer: D

2.The "maximum occupancy" of a room is the total number of people who can be in

a room without causing a fire hazard. In a large room, a Fire Safety Code states

that the maximum occupancy is 1 person for every 7 square feet (ft2). A college is hosting a concert in a hall that is 14,721 ft2, and 1,000 people are expected to attend. According to the Fire Safety Code, approximately how many more people can attend the concert without causing a fire hazard?

A.900 people

B.1,000 people