Unit Rates Answers

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A technician is testing light bulbs to determine the number of defective bulbs. The technician records the table below to show the results.Result of Light Bulb TestNumber of Bulbs Tested142884336Number of Defective Bulbs Found126?The technician expects to find 24 defective bulbs when 336 are tested. Which statement explains whether the technician’s reasoning is correct, based on the information in the table?

A
The reasoning is correct. The ratio of number of bulbs tested to defective bulbs is always 14 to 1.
B
The reasoning is correct. The number of defective bulbs doubles, then triples, so the next number should be four times larger, regardless of the number of bulbs tested.
C
The reasoning is not correct because the technician should have found the difference between 336 and 84, then divided the result by 6.
D
The reasoning is not correct because the first two values in each row is doubled, so the technician should have doubled 6 to get the missing value.
6

One pound of grapes costs $1.55. Which equation correctly shows a pair of equivalent ratios that can be used to find the cost of 3.5 pounds of grapes?

A
StartFraction 1.55 over 1 EndFraction = StartFraction x over 3.5 EndFraction
Option A
B
StartFraction 1.55 over 1 EndFraction = StartFraction 3.5 over x EndFraction
Option B
C
StartFraction 1 over 1.55 EndFraction = StartFraction x over 3.5 EndFraction
Option C
D
StartFraction x over 1.55 EndFraction = StartFraction 1 over 3.5 EndFraction
Option D
8

The ratio of girls to boys in a classroom is 3:5. Kevin says there must be 8 students in the classroom. Which explains whether Kevin is correct?

A
Kevin is correct because 3 girls + 5 boys = 8 students.
B
Kevin is correct because 5 girls + 3 boys = 8 students.
C
Kevin is incorrect because 3:5 may be a simplified ratio.
D
Kevin is incorrect because the ratio 3:5 does not compare different units.
9

A car travels 22 miles for every gallon of gasoline used. The table below represents this relationship.Gas MileageDistance Traveled(miles)Gasoline Used(gallons)221442x3884Which equation correctly shows a pair of equivalent ratios that can be used to find the unknown?

A
StartFraction 1 over 22 EndFraction = StartFraction x over 2 EndFraction
Option A
B
StartFraction 22 over 1 EndFraction = StartFraction x over 2 EndFraction
Option B
C
StartFraction 1 over 22 EndFraction = StartFraction x over 3 EndFraction
Option C
D
StartFraction 22 over 1 EndFraction = StartFraction x over 3 EndFraction
Option D
10

At one farmer’s market, bananas cost $0.80 per pound. At another farmer’s market, bananas are sold in 5-pound bags for $4.50 per bag. Which explains how to find the better buy?

A
Divide 4.50 by 5 to find the unit rate for the 5-pound bag, and compare that number to $0.80 per pound.
B
Divide 0.80 by 5 to find the unit rate for the 5-pound bag, and compare that number to $0.80 per pound.
C
Multiply 4.50 by 5 to find the cost for 5 pounds, and compare to $4.50 per bag.
D
Multiply 4.50 by 0.80 to find the cost for 5 pounds, and compare to $4.50 per bag.

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