PSAT Math : PSAT Mathematics

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #2 : Operations With Fractions

If a car travels at 30 mph, how many feet per second does travel?

Possible Answers:

440 ft/s

2,640 ft/s

44 ft/s

264 ft/s

4,400 ft/s

Correct answer:

44 ft/s

Explanation:

30 miles / 1 hour  *  5280 ft / 1 mile * 3600 seconds / 1 hour = 44 ft/sec

Example Question #1 : How To Multiply Fractions

In a group of 20 children, 25% are girls.  How many boys are there?

Possible Answers:

15

5

4

16

10

Correct answer:

15

Explanation:

Since \dpi{100} \small \frac{1}{4} of the children are girls, this totals to \dpi{100} \small 20 \times \frac{1}{4} = 5 girls in the group.

\dpi{100} \small 20-5=15 boys.

Example Question #121 : Fractions

Possible Answers:

Correct answer:

Explanation:

Remember, when you multiply fractions, you can directly multiply their denominators and their numerators; therefore, you can begin this problem by making it into one large fraction:

Now, you could multiply all of this out and then divide. However, you can cancel things immediately. The  goes into the  and the  into the . Thus, you have:

Example Question #122 : Fractions

Simplify:

Possible Answers:

Correct answer:

Explanation:

First, begin by remembering that  is the same as :

Next, recall that you multiply fractions by multiplying the numerators and denominators by each other. It is very simple. This would give you:

Now, you can cancel the  and the :

Next, you can reduce the  and the :

You can also reduce the resulting  and the :

Example Question #1 : How To Add Fractions

Jesse has a large movie collection containing X movies. 1/3 of his movies are action movies, 3/5 of the remainder are comedies, and the rest are historical movies. How many historical movies does Jesse own?

Possible Answers:

(4/15)*X

(3/9)*X

(7/12)*X

(2/5)*X

(11/15)*X

Correct answer:

(4/15)*X

Explanation:

1/3 of the movies are action movies. 3/5 of 2/3 of the movies are comedies, or (3/5)*(2/3), or 6/15. Combining the comedies and the action movies (1/3 or 5/15), we get 11/15 of the movies being either action or comedy. Thus, 4/15 of the movies remain and all of them have to be historical.

Example Question #12 : Operations With Fractions

If x = 1/3 and y = 1/2, find the value of 2x + 3y.

Possible Answers:

5/6

2

6/5

13/6

1

Correct answer:

13/6

Explanation:

Substitute the values of x and y into the given expression:

2(1/3) + 3(1/2)

= 2/3 + 3/2

= 4/6 + 9/6

= 13/6

Example Question #131 : Arithmetic

Alternating1

Possible Answers:

\dpi{100} -\frac{47}{60}

\dpi{100} -\frac{43}{60}

\dpi{100} \frac{47}{60}

\dpi{100} \frac{17}{60}

\dpi{100} \frac{43}{60}

Correct answer:

\dpi{100} \frac{47}{60}

Explanation:

Alternating2

Alternating3

Example Question #131 : Arithmetic

Solve \frac{3}{7}+\frac{5}{8}-\frac{1}{2}.

Possible Answers:

\frac{31}{56}

\frac{7}{8}

\frac{33}{56}

\frac{5}{7}

Correct answer:

\frac{31}{56}

Explanation:

Finding the common denominator yields \frac{24}{56}+\frac{35}{56}-\frac{28}{56}. We can then evaluate leaving \frac{31}{56}.

Example Question #612 : Arithmetic

What is the solution, reduced to its simplest form, for x = \frac{7}{9}+\frac{3}{5}+\frac{2}{15}+\frac{7}{45}} ?

Possible Answers:

x = \frac{75}{45}

x = \frac{7}{15}

x = \frac{115}{45}

x = \frac{5}{3}

x =2

Correct answer:

x = \frac{5}{3}

Explanation:

x=\frac{7}{9}+\frac{3}{5}+\frac{2}{15}+\frac{7}{45}=\frac{35}{45}+\frac{27}{45}+\frac{6}{45}+\frac{7}{45}=\frac{75}{45}=\frac{5}{3}

Example Question #3 : How To Add Fractions

What is the sum of  and ?

Possible Answers:

Correct answer:

Explanation:

We can begin by eliminating the obviously wrong answers. We know that the sum of the two fractions will be more than 1, so the answer choices  and  are out. Now, let's add the two fractions:

Begin by converting  to .

Now find the common denominator of  and . The least common multiple of 5 and 6 is 30, so 30 is the common denominator. Now alter both fractions so that they use the common denominator:

 

Now we can easily add the two fractions together:

The answer is .

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