HSPT Quantitative : How to manipulate numbers

Study concepts, example questions & explanations for HSPT Quantitative

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Example Questions

Example Question #111 : How To Manipulate Numbers

What is the average of \(\displaystyle 15^2\)\(\displaystyle 16^2\), and the product of \(\displaystyle 14\) and \(\displaystyle 16\)?

Possible Answers:

\(\displaystyle 235\)

\(\displaystyle 225\)

\(\displaystyle 210\)

\(\displaystyle 239\)

Correct answer:

\(\displaystyle 235\)

Explanation:

First, calculate each of the three values:

\(\displaystyle 15^2=225\)

\(\displaystyle 16^2=256\)

\(\displaystyle 14\cdot16=224\)

Then, find the average by dividing the sum by the number of values:

\(\displaystyle \frac{225+256+224}{3}=\frac{705}{3}=235\)

Example Question #112 : How To Manipulate Numbers

\(\displaystyle 42\) is \(\displaystyle 20\) percent of what number?

Possible Answers:

\(\displaystyle 810\)

\(\displaystyle 840\)

\(\displaystyle 210\)

\(\displaystyle 284\)

Correct answer:

\(\displaystyle 210\)

Explanation:

Set up a ratio to solve this problem, using an \(\displaystyle x\) to represent the unknown value:

\(\displaystyle \frac{42}{x}=\frac{20}{100}\)

Then cross multiply and solve:

\(\displaystyle 42\cdot100=20x\)

\(\displaystyle 4200=20x\)

\(\displaystyle \frac{4200}{20}=x\)

\(\displaystyle 210=x\)

Example Question #113 : How To Manipulate Numbers

\(\displaystyle 44\) is what percent of \(\displaystyle 400\)?

Possible Answers:

\(\displaystyle 20\)

\(\displaystyle 11\)

\(\displaystyle 176\)

\(\displaystyle 17.6\)

Correct answer:

\(\displaystyle 11\)

Explanation:

Set up a ratio to solve this problem:

\(\displaystyle \frac{44}{400}=\frac{x}{100}\)

Then cross-multiply and solve:

\(\displaystyle 44\cdot100=400x\)

\(\displaystyle \frac{4400}{400}=11=x\)

Example Question #114 : How To Manipulate Numbers

What number, when multiplied by \(\displaystyle 2\), is \(\displaystyle \frac{1}{3}\) of \(\displaystyle 96\)?

Possible Answers:

\(\displaystyle 24\)

\(\displaystyle 16\)

\(\displaystyle 18\)

\(\displaystyle 19\)

Correct answer:

\(\displaystyle 16\)

Explanation:

First, find  \(\displaystyle \frac{1}{3}\) of \(\displaystyle 96\):

\(\displaystyle \frac{96}{3}=32\)

Then, divide by \(\displaystyle 2\):

\(\displaystyle 32\div2=16\)

Example Question #115 : How To Manipulate Numbers

What is \(\displaystyle 4\) times \(\displaystyle \frac{1}{2}\) of \(\displaystyle 22\)?

Possible Answers:

\(\displaystyle 33\)

\(\displaystyle 44\)

\(\displaystyle 88\)

\(\displaystyle 22\)

Correct answer:

\(\displaystyle 44\)

Explanation:

First, \(\displaystyle \frac{1}{2}\) of \(\displaystyle 22\) is \(\displaystyle 11\):

\(\displaystyle \frac{22}{2}=11\)

Next, multiply by \(\displaystyle 4\):

\(\displaystyle 11\cdot4=44\)

 

Example Question #116 : How To Manipulate Numbers

What is \(\displaystyle 30\) percent of \(\displaystyle 660\)?

Possible Answers:

\(\displaystyle 168\)

\(\displaystyle 212\)

\(\displaystyle 198\)

\(\displaystyle 210\)

Correct answer:

\(\displaystyle 198\)

Explanation:

Multiply by the decimal version of \(\displaystyle 30\) percent:

\(\displaystyle 660\cdot.30=198\)

Example Question #117 : How To Manipulate Numbers

What is \(\displaystyle 6\) less than \(\displaystyle \frac{3}{4}\) of \(\displaystyle 52\)?

Possible Answers:

\(\displaystyle 39\)

\(\displaystyle 33\)

\(\displaystyle 37\)

\(\displaystyle 40\)

Correct answer:

\(\displaystyle 33\)

Explanation:

First, find \(\displaystyle \frac{3}{4}\) of \(\displaystyle 52\):

\(\displaystyle \frac{3\cdot52}{4}=39\)

Then subtract \(\displaystyle 6\):

\(\displaystyle 39-6=33\)

Example Question #118 : How To Manipulate Numbers

What number, multiplied by \(\displaystyle 3\), is equal to \(\displaystyle 2\) times the square root of \(\displaystyle 81\)?

Possible Answers:

\(\displaystyle 18\)

\(\displaystyle 12\)

\(\displaystyle 6\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle 6\)

Explanation:

First, find the square root of \(\displaystyle 81\):

\(\displaystyle \sqrt{81}=9\)

Then, multiply by \(\displaystyle 2\):

\(\displaystyle 9\cdot2=18\)

And finally divide by \(\displaystyle 3\):

\(\displaystyle 18\div3=6\)

Example Question #119 : How To Manipulate Numbers

What is \(\displaystyle 14\) percent of \(\displaystyle 180\)?

Possible Answers:

\(\displaystyle 42\)

\(\displaystyle 45\)

\(\displaystyle 25.2\)

\(\displaystyle 33\)

Correct answer:

\(\displaystyle 25.2\)

Explanation:

Set up a ratio to solve this problem, representing the unknown value with an \(\displaystyle x\):

\(\displaystyle \frac{x}{180}=\frac{14}{100}\)

Then cross-multipy and solve:

\(\displaystyle 180\cdot14=100x\)

\(\displaystyle \frac{180\cdot14}{100}=\frac{18\cdot 14}{10}=\frac{9\cdot 14}{5}=\frac{126}{5}=25.2=x\)

Example Question #120 : How To Manipulate Numbers

What is the difference between \(\displaystyle \frac{1}{3}\) of \(\displaystyle 36\) and \(\displaystyle \sqrt{36}\)?

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle 9\)

\(\displaystyle 3\)

\(\displaystyle 6\)

Correct answer:

\(\displaystyle 6\)

Explanation:

 \(\displaystyle \frac{1}{3}\) of \(\displaystyle 36\) is 

\(\displaystyle \frac{36}{3}=12\)

and \(\displaystyle \sqrt{36}\) is \(\displaystyle 6\) (because \(\displaystyle 6\cdot6=36\))

Subtract to find the difference:

\(\displaystyle 12-6=6\)

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