GED Math : Proportions and Percentages

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #72 : Complex Operations

Ten percent of a number is six more than 5 percent of this number.  Find the number.

Possible Answers:

Correct answer:

Explanation:

The key word "is" indicates equality.

 

Ten percent of a number:  

 

Six more than 5 percent of this number: 

 

Solve and simplify:  

Example Question #401 : Ged Math

45% of what number is 9?

Possible Answers:

Correct answer:

Explanation:

The rate is 45% and the comparative number is 9; the unknown is the original number that 9 is 45% of.  The statement is "(nine) is (forty-five percent) of (some number)", so the variable stands for a number.

 

Example Question #407 : Ged Math

A building that is  casts a shadow that is  long.  At the same time, another tree casts a shadow that is  long.  How tall is that tree?

Possible Answers:

Correct answer:

Explanation:

To solve this you would set up and solve a direct proportion:

 

 

 

Example Question #408 : Ged Math

Bob's Bargain Basement has computer tables on sale at 50% off the retail price. For the holiday, an additional 15% is deducted.  If the computer table is $240, how much is the table on sale for during the holiday?

Possible Answers:

Correct answer:

Explanation:

In order to calculate the amount of the purchase, you first must find the cost of the table at 50% off.  This can be done by taking  of the original cost.

This could also be done by converting the percent to a decimal and then multiplying that decimal by the original cost.

Then, the next step would be to take 15% of the $120.  This is done by converting the percent to a decimal and then multiplying by $120.

15% = .15 as a decimal

This additional savings of $18.00 would then be subtracted from the $120.00.

 

This is the amount that will be paid after all discounts and savings.  

 

Note:  Do not add the initial savings of 50% to the additional savings of 15% to get a total savings of 65% and then work your problem from there.  That is not the correct way to work this problem!

Example Question #402 : Ged Math

Solve:  

Possible Answers:

Correct answer:

Explanation:

Cross multiply the terms.

Divide by eight on both sides.

The answer is:  

Example Question #410 : Ged Math

What is 30% of 750?

Possible Answers:

Correct answer:

Explanation:

To find a percentage of a whole number, we will multiply the percentage by the whole number. So, we get

 

 

To make things easier, we will simply by cancelling out the zeros. So, we get

 

 

 

 

Therefore, 30% of 750 is 225.

Example Question #41 : Proportions And Percentages

What is 90% of 750?

Possible Answers:

Correct answer:

Explanation:

To find a percentage of a whole number, we will multiply the percentage by the whole number.

So, we get

To simplify, we can cancel. The zeros will cancel each other out. We get

Therefore, 90% of 750 is 675.

Example Question #42 : Proportions And Percentages

Solve the proportion:  

Possible Answers:

Correct answer:

Explanation:

Cross multiply the terms.

Divide by six on both sides.

The answer is:  

Example Question #43 : Proportions And Percentages

Solve the proportion:  

Possible Answers:

Correct answer:

Explanation:

Cross multiply the terms.

Distribute the terms.

Subtract  on both sides.

Divide or multiply by negative one to isolate the x-variable.

The answer is:   

Example Question #44 : Proportions And Percentages

Solve the proportion:  

Possible Answers:

Correct answer:

Explanation:

Cross multiply the terms.

Divide by 24 on both sides.

Reduce the fractions.

The answer is:  

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