SSAT Upper Level Math : Compound Fractions

Study concepts, example questions & explanations for SSAT Upper Level Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 : Compound Fractions

Simplify:

\displaystyle \frac{1+\frac{1}{x}}{3+\frac{3}{x}}

 

Possible Answers:

\displaystyle \frac{1}{3}

\displaystyle \frac{X+1}{X+3}

\displaystyle 3

\displaystyle 1

\displaystyle 4

Correct answer:

\displaystyle \frac{1}{3}

Explanation:

Simplify into a complex fraction for the numerator and denominator.

For the numerator, we need to multiply \displaystyle 1\cdot \left(\frac{x}{x}\right) then the top should read \displaystyle \frac{x+1}{x}.

For the bottom, we need to multiply \displaystyle 3 \cdot \left(\frac{x}{x} \right ) in order to add the components. Thus the bottom should read \displaystyle \frac{3x+3}{x}.

Dividing fractions is the same as multiplying the numerator by the reciprocal of the denominator.

Therefore, multiply top and bottom by \displaystyle \frac{x}{3x+3} and then you should see that if you factor a \displaystyle 3 on the bottom, the \displaystyle x+1 cancels along with the \displaystyle x's.

\displaystyle \frac{x+1}{x}\cdot \frac{x}{3x+3}\rightarrow \frac{x+1}{x}\cdot \frac{x}{3(x+1)}=\frac{1}{3}

The answer then should be \displaystyle \frac{1}{3}

Example Question #2 : How To Find A Solution To A Compound Fraction

Convert \displaystyle 6\frac{1}{3} into a fraction. 

Possible Answers:

\displaystyle \frac{19}{3}

\displaystyle \frac{64}{3}

\displaystyle \frac{17}{3}

\displaystyle \frac{10}{3}

\displaystyle \frac{18}{3}

Correct answer:

\displaystyle \frac{19}{3}

Explanation:

The whole number \displaystyle (6) is multipled by the denominator \displaystyle (3). Then we add the numerator \displaystyle (1). This value is divided by the denominator. Final answer is \displaystyle \frac{19}{3}.

Example Question #3 : How To Find A Solution To A Compound Fraction

Convert  to an improper fraction. 

Possible Answers:

\displaystyle {}\frac{47}{5}

\displaystyle \frac{78}{5}

\displaystyle \frac{23}{5}

\displaystyle \frac{90}{5}

\displaystyle \frac{16}{5}

Correct answer:

\displaystyle {}\frac{47}{5}

Explanation:

To convert into an improper fraction, take the whole number \displaystyle (9) and multiply that with the denominator \displaystyle (5).

\displaystyle 9\cdot 5=45

 

Then, we add that to the numerator which is \displaystyle 2.

\displaystyle 45+2=47

Then we take that sum and put it over th denominator \displaystyle (5) which gives us an answer of:

 \displaystyle {}\frac{47}{5}

Example Question #1352 : Ssat Upper Level Quantitative (Math)

Simplify.

\displaystyle \frac{\frac{6}{7}}{\frac{8}{3}}\cdot \frac{4}{5}

Possible Answers:

\displaystyle \frac{9}{35}

\displaystyle \frac{64}{35}

\displaystyle \frac{9}{112}

\displaystyle \frac{45}{112}

\displaystyle \frac{30}{51}

Correct answer:

\displaystyle \frac{9}{35}

Explanation:

Lets focus on the left fraction. Lets try to have three fractions multipled altogether. To acheive this, we can multiply the numerator of the left fraction with the reciprocal of the denominator.

Thus, mutliple the numerator and denominator by \displaystyle \frac{3}{8}.  

Now we have \displaystyle \frac{6}{7}\cdot \frac{3}{8} \cdot \frac{4}{5}. We can simplify this by crossing out the \displaystyle 4 to a \displaystyle 1 and the \displaystyle 8 to a \displaystyle 2.

Then, cross out the \displaystyle 2 into a \displaystyle 1 and the \displaystyle 6 into a \displaystyle 3. It should look like this:

\displaystyle \frac{3}{7}\cdot \frac{3}{1}\cdot \frac{1}{5}.

Multiply it out and you will get the answer.

\displaystyle \frac{3}{7}\cdot \frac{3}{1}\cdot \frac{1}{5}=\frac{9}{35}

Example Question #5 : How To Find A Solution To A Compound Fraction

Solve and simplify.

\displaystyle \frac{3-\frac{7}{4}}{6-\frac{7}{8}}

Possible Answers:

\displaystyle \frac{1}{4}

\displaystyle \frac{2}{5}

\displaystyle \frac{7}{8}

\displaystyle \frac{205}{32}

\displaystyle \frac{10}{41}

Correct answer:

\displaystyle \frac{10}{41}

Explanation:

Convert both numerator and denominators into fractions. Convert the integers first to fractions. 

\displaystyle 3 \cdot \frac{4}{4}=\frac{12}{4}

\displaystyle 6 \cdot \frac{8}{8}=\frac{48}{8}

Now that our numerator and denominator have a common denominator between their fractions we can subtract them.

\displaystyle \frac{\frac{12}{4}-\frac{7}{4}}{\frac{48}{8}-\frac{7}{8}}=\frac{\frac{5}{4}}{\frac{41}{8}}

Then multiply top and bottom by \displaystyle \frac{8}{41} as that is the reciprocal of the denominator and when dividing fractions, it is the same as multiplying the numerator by the reciprocal of the denominator.

\displaystyle \frac{5}{4}\cdot \frac{8}{41} 

Then reduce by crossing out the \displaystyle 4 into a \displaystyle 1 and the \displaystyle 8 into a \displaystyle 2.

Then multiply to get the answer.

\displaystyle \frac{5}{1}\cdot \frac{2}{41}=\frac{10}{41} 

 

Example Question #1 : Compound Fractions

Solve and simplify.

\displaystyle \frac{1}{2}+\frac{1}{3}\cdot \frac{6}{7}+\frac{1}{5}

Possible Answers:

\displaystyle \frac{69}{70}

\displaystyle \frac{37}{42}

\displaystyle \frac{71}{70}

\displaystyle \frac{32}{35}

\displaystyle \frac{6}{175}

Correct answer:

\displaystyle \frac{69}{70}

Explanation:

Remember PEMDAS, the order of operations for dealing with expressions which is the acronym that stands for (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction).

Multiplication has priority over addition. Looking at the fractions that are multiplied together we can see the \displaystyle 3 is reduced to \displaystyle 1 and the \displaystyle 6 into a \displaystyle 2.

The new fraction becomes: 

\displaystyle \frac{1}{2}+\frac{2}{7}+\frac{1}{5} 

Then find least common denominator. In our case it will be 70.

\displaystyle \frac{1}{2}\cdot \frac{35}{35}+\frac{2}{7}\cdot \frac{10}{10}+\frac{1}{5}\cdot \frac{14}{14}\rightarrow \displaystyle \frac{35}{70}+\frac{20}{70}+\frac{14}{70}.

Then add it all up to get the final answer.

\displaystyle \frac{35}{70}+\frac{20}{70}+\frac{14}{70}=\frac{69}{70} 

Example Question #3 : Compound Fractions

Simplify.

\displaystyle \frac{14}{4}\left(\frac{3}{7}+\frac{96}{21}\right)-8\left(\frac{17}{8}+\frac{100}{16}\right)

Possible Answers:

\displaystyle -\frac{45}{2}

\displaystyle \frac{99}{2}

\displaystyle \frac{45}{2}

\displaystyle -\frac{99}{2}

\displaystyle \frac{34}{7}

Correct answer:

\displaystyle -\frac{99}{2}

Explanation:

Remember PEMDAS. Take care of the parentheses first and find least common denominator of the fractions. Next distribute, then add and finally, subtract. 

\displaystyle \frac{14}{4}\left(\frac{9}{21}+\frac{96}{21}\right)-8\left(\frac{34}{16}+\frac{100}{16}\right)

Working with the parentheses we get:

\displaystyle \frac{14}{4}\left( \frac{105}{21}\right)-8\left(\frac{134}{16}\right) 

Reduce the \displaystyle 14 to \displaystyle 2 and the \displaystyle 21 to \displaystyle 3. Then reduce \displaystyle 8 to \displaystyle 1 and \displaystyle 16 to \displaystyle 2.

\displaystyle \frac{2}{4}\cdot \frac{105}{3}-\frac{134}{2} 

Multiply first then subtract.

\displaystyle \frac{210}{12}-\frac{134}{2} 

If I divide the left fraction by \displaystyle 6, I should be able to match the denominator of the right fraction and also I can subtract easily.

\displaystyle \frac{35}{2}-\frac{134}{2}=-\frac{99}{2}

Learning Tools by Varsity Tutors