SAT - Rates, proportions and percents- chapter 4

A price reduction from $150 to $120 is what percent change?

If there are 60 seconds in a minute, 60 minutes in an hour, and 5,280 feet in a mile, how many feet per second are equivalent to 40 miles per hour?

A 20 percent increase in output from 45 units/hour results in an output of how many units/hour?

The sum of three numbers is 576. One of the numbers, n, is 25 percent more than the sum of the other two numbers. What is the value of n?

A beard-second is equal to 5 nanometers, and 1,000 nanometers is equal to 1 micrometer. How many beard-seconds are in 16 micrometers?

• 0.08

• 12.5

• 312.5

• 3200

Kuam’s annual salary is $57,390. If he worked 30 hours each week last year, which is the closest to the average amount he earned, in dollars per hour? (Note: 1 year = 52 weeks)

• 22

• 28

• 37

• 40

A food company mixes a gallons of a 20 percent vinegar solution with b gallons of a 50 percent vinegar solution in order to create a 38 percent vinegar solution. The equation above represents this situation. If the company uses 1,000 gallons of the 50 percent vinegar solution, approximately how many gallons of the 20 percent vinegar solution will it need to use?

• 433

• 667

• 967

• 1033

The number of gallons of fuel consumed is directly proportional to the number of minutes traveled. After 30 minutes of traveling, 0.6 gallons of fuel are consumed. How many gallons of fuel are consumed after 90 minutes of traveling?

• 0.2

• 0.8

• 1

• 1.8

Michelle is replenishing inventory for her jewelry store. She has 12 necklaces and 18 bracelets in stock. She has ordered an additional 22 necklaces. How many more bracelets does she need to order so that 3/5 of the total necklaces and bracelets in stock will be bracelets?

• 18

• 24

• 27

• 33

One solution that comprises a quarter of a mixture of two solutions contains 40 percent chemical A. If the total mixture contains 16 percent chemical A, what percentage chemical A does the second solution that makes up the mixture contain?

• 8

• 10

• 12

• 14

Answer explanation

The second chemical makes up three-quarters of the final mixture, so set up the equation 1/4 (40) + 3/4 x = 16. (Since all the values are in percents, there is no need to convert to decimals.) Solve to find that 3/4 x = 16 − 10, So 3/4 x = 6. Multiply both sides by 4/3 to get x, which is 8%.