Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi
Undefined control sequence \dpi





PSAT Math : How to divide fractions

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : How To Divide Fractions

Simplify:

  Sat_math_167_03

 

 

Possible Answers:

ad/bc

a/b/c/d

It is already in simplest terms

a2/c2

ac/bd

Correct answer:

ad/bc

Explanation:

Division is the same as multiplying by the reciprocal.  Thus, a/b ÷ c/d = a/b x d/c = ad/bc

 

 

Example Question #1 : Operations With Fractions

If p is a positive integer, and 4 is the remainder when p-8 is divided by 5, which of the following could be the value of p?

Possible Answers:

17

20

18

19

Correct answer:

17

Explanation:

Remember that if x has a remainder of 4 when divided by 5, x minus 4 must be divisible by 5. We are therefore looking for a number p such that p - 8 - 4 is divisible by 5. The only answer choice that fits this description is 17. 

Example Question #1 : How To Divide Fractions

If \dpi{100} \small x=\frac{2}{3} and \dpi{100} \small y= \frac {3}{4}, then what is the value of \dpi{100} \small \frac {x}{y}?

Possible Answers:

\dpi{100} \small \frac{5}{7}

\dpi{100} \small 2

\dpi{100} \small \frac{9}{8}

\dpi{100} \small \frac{8}{9}

\dpi{100} \small \frac{1}{2}

Correct answer:

\dpi{100} \small \frac{8}{9}

Explanation:

Dividing by a number (in this case \dpi{100} \small \frac {3}{4}) is equivalent to multiplying by its reciprocal (in this case \dpi{100} \small \frac {4}{3}).  Therefore:

\dpi{100} \small \frac {2}{3}\div \frac{3}{4} = \frac{2}{3}\times \frac{4}{3} = \frac{8}{9}

Example Question #2 : How To Divide Fractions

Evaluate the following:

\displaystyle \left ( \frac{5}{6}\times \frac{12}{13} \right )^{2}\div \frac{3}{4}

Possible Answers:

\frac{400}{507}\displaystyle \frac{400}{507}

\frac{507}{400}\displaystyle \frac{507}{400}

\frac{4}{5}\displaystyle \frac{4}{5}

\frac{25}{507}\displaystyle \frac{25}{507}

None of the available answers

Correct answer:

\frac{400}{507}\displaystyle \frac{400}{507}

Explanation:

\displaystyle \left ( \frac{5}{6}\times \frac{12}{13} \right )^{2}\div \frac{3}{4}

First we will evaluate the terms in the parentheses:

\displaystyle \left ( \frac{5}{6}\times \frac{2\times 6}{13} \right )^{2}\div \frac{3}{4}

\displaystyle \left ( \frac{5}{1}\times \frac{2}{13} \right )^{2}\div \frac{3}{4}

\displaystyle \left ( \frac{10}{13} \right )^{2}\div \frac{3}{4}

Next, we will square the first fraction:

\displaystyle \left ( \frac{10^{2}}{13^{2}} \right )\div \frac{3}{4}

\frac{100}{169}\div \frac{3}{4}\displaystyle \frac{100}{169}\div \frac{3}{4}

We can evaluate the division as such:

\frac{100}{169}\times\frac{4}{3}=\frac{400}{507}\displaystyle \frac{100}{169}\times\frac{4}{3}=\frac{400}{507}

Example Question #1 : How To Divide Fractions

Simplify: \displaystyle \frac{\frac{3x}{2}}{\frac{5x}{4}}

Possible Answers:

\displaystyle \frac{6}{5}

\displaystyle \frac{15x^{2}}{8}

\displaystyle \frac{15x}{8}

\displaystyle 6x

\displaystyle \frac{15x}{2}

Correct answer:

\displaystyle \frac{6}{5}

Explanation:

Start by rewriting this fraction as a division problem:

\displaystyle \frac{3x}{2}\div \frac{5x}{4}

When dividing fractions, you multiply by the reciprocal of the second fraction, so you can rewrite your problem like this:

\displaystyle \frac{3x}{2}\times \frac{4}{5x}

Multiply across the numerators and then across the denominators to get \displaystyle \frac{12x}{10x}. The x's cancel, and you can reduce the fraction to be \displaystyle \frac{6}{5}.

Example Question #3 : How To Divide Fractions

Define an operation \displaystyle \otimes \; as follows:

For all real numbers \displaystyle a ,b,

\displaystyle a \otimes b = \frac{4-a}{b}.

Evaluate \displaystyle 1 \frac{1}{2} \otimes 2 \frac{1}{3}.

Possible Answers:

\displaystyle 5\frac{5}{6}

\displaystyle 1 \frac{1}{14}

\displaystyle \frac{14}{15}

\displaystyle \frac{6}{35}

\displaystyle 1\frac{1}{6}

Correct answer:

\displaystyle 1 \frac{1}{14}

Explanation:

\displaystyle a \otimes b = \frac{4-a}{b}, or, equivalently,

\displaystyle a \otimes b =( 4-a ) \div b

\displaystyle 1 \frac{1}{2} \otimes 2 \frac{1}{3} =\left ( 4-1 \frac{1}{2} \right ) \div 2 \frac{1}{3}

\displaystyle = 2 \frac{1}{2} \div 2 \frac{1}{3}

\displaystyle = \frac{5}{2} \div \frac{7}{3}

\displaystyle = \frac{5}{2} \times \frac{3}{7}

\displaystyle = \frac{15}{14}

\displaystyle = 1 \frac{1}{14}

Example Question #2 : How To Divide Fractions

Define an operation \displaystyle \odot as follows:

For all real numbers \displaystyle a ,b,

\displaystyle a \odot b = \frac{a}{b+2}.

Evaluate \displaystyle \frac{3}{5} \odot \frac{1}{5}.

Possible Answers:

\displaystyle 1

\displaystyle \frac{25}{33}

\displaystyle 1\frac{8}{25}

\displaystyle 3\frac{2}{3}

\displaystyle \frac{3} {11}

Correct answer:

\displaystyle \frac{3} {11}

Explanation:

\displaystyle a \odot b = \frac{a}{b+2},

or, equivalently, 

\displaystyle a \odot b = a \div\left ( b+2 \right )

\displaystyle \frac{3}{5} \odot \frac{1}{5}= \frac{3}{5} \div \left (\frac{1}{5}+2 \right )

\displaystyle = \frac{3}{5} \div \frac{11}{5}

\displaystyle = \frac{3}{5} \cdot \frac{5}{11}

\displaystyle = \frac{3}{1} \cdot \frac{1}{11}

\displaystyle = \frac{3} {11}

 

Example Question #1 : How To Divide Fractions

Define an operation  as follows:

For all real numbers \displaystyle a ,b,

.

Evaluate .

Possible Answers:

\displaystyle \frac{4}{25}

\displaystyle 16

\displaystyle 976\frac{9}{16}

\displaystyle 100

\displaystyle \frac{16} {25}

Correct answer:

\displaystyle \frac{16} {25}

Explanation:

\displaystyle = 25 \div \left ( \frac{25}{4} \right ) ^{2}

\displaystyle = 25 \div \left ( \frac{625}{16} \right )

\displaystyle = \frac{25 }{1}\times \left ( \frac{16} {625}\right )

\displaystyle = \frac{1}{1}\times \left ( \frac{16} {25}\right )

\displaystyle = \frac{16} {25}

Example Question #3 : How To Divide Fractions

Define an operation \displaystyle \ominus as follows:

For all real numbers \displaystyle a ,b,

\displaystyle a \; \ominus \; b = a^{2} \div b.

Evaluate \displaystyle 16 \; \ominus \; 3\frac{1}{5}.

Possible Answers:

\displaystyle 80

\displaystyle 1\frac{9}{16}

\displaystyle \frac{5}{16}

\displaystyle 25

\displaystyle 819\frac{1}{5}

Correct answer:

\displaystyle 80

Explanation:

\displaystyle a \; \ominus \; b = a^{2} \div b

\displaystyle 16 \; \ominus \; 3\frac{1}{5} = 16^{2} \div 3\frac{1}{5}

\displaystyle = 256 \div \frac{16}{5}

\displaystyle = \frac{256 }{1}\times \frac{5}{16}

\displaystyle = \frac{16}{1}\times \frac{5}{1}

\displaystyle = 16 \times 5 = 80

Example Question #4 : How To Divide Fractions

Define an operation \displaystyle \amalg as follows:

For all real numbers \displaystyle a ,b,

\displaystyle a \amalg b = 5 - \frac{a}{b}.

Evaluate \displaystyle 1 \frac{1}{2}\; \amalg \; 2 \frac{1}{3}.

Possible Answers:

\displaystyle 3\frac{4}{9}

\displaystyle 4\frac{5}{7}

\displaystyle 4 \frac{5}{14}

The correct answer is not among the other responses.

\displaystyle 1\frac{1}{2}

Correct answer:

\displaystyle 4 \frac{5}{14}

Explanation:

\displaystyle a \amalg b = 5 - \frac{a}{b}

or, equivalently,

\displaystyle a \amalg b = 5 - a \div b

\displaystyle 1 \frac{1}{2}\; \amalg \; 2 \frac{1}{3}= 5 - 1 \frac{1}{2} \div 2 \frac{1}{3}

\displaystyle = 5 - \frac{3}{2} \div \frac{7}{3}

\displaystyle = 5 - \frac{3}{2} \times \frac{3}{7}

\displaystyle = 5 - \frac{9}{14}

\displaystyle = 4 \frac{5}{14}

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