GED Math : Complex Operations

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #31 : Proportions And Percentages

Gerald's current monthly rent is $720. His rent will increase by 20% starting in January; it will increase by $50 starting in July. How much rent will Gerald pay from January to December?

Possible Answers:

Correct answer:

Explanation:

If Gerald's current rent is $720, then a 20% increase in rent will be an increase of

.

This makes Gerald's rent from January to June

.

His rent from July to December will be $50 more than this, or 

.

Over the next year, Gerald will pay $864 in monthly rent for six months, then $914 in monthly rent for six months. This is

in rent total.

Example Question #31 : Proportions And Percentages

Quinn invests $6,000 in stocks and bonds. He invests 60% of the money in corporate bonds which, over the next year, return 8%. The remainder, he invests in a preferred stock, which ends up producing a loss of 4%. How much money has Quinn gained or lost from his investments?

Possible Answers:

Quinn has gained $192

Quinn has gained $384

Quinn has lost $192

Quinn has lost $384

Correct answer:

Quinn has gained $192

Explanation:

60% of 6,000 is , so this is what Quinn has invested in the bonds. The bonds return 8% of this, or 

.

Quinn invests  in stock. It yields a loss of 4% of this, or

.

Quinn has a net gain of 

from his investments.

Example Question #72 : Complex Operations

Seven tenths of three fourths of  is what percent of ?

Possible Answers:

Correct answer:

Explanation:

Seven tenths of three fourths of  is equal to

.

 of a number, converted to percent, is

.

Example Question #73 : Complex Operations

What is 40% of 80% of ?

Possible Answers:

Correct answer:

Explanation:

80% of  is  multiplied by , or .

40% of this is  multiplied by ; this is 

.

Example Question #41 : Proportions And Percentages

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 #71 : Complex Operations

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 #75 : Complex Operations

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 #44 : Proportions And Percentages

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 #45 : Proportions And Percentages

Solve:  

Possible Answers:

Correct answer:

Explanation:

Cross multiply the terms.

Divide by eight on both sides.

The answer is:  

Example Question #42 : Proportions And Percentages

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.

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