All PSAT Math Resources
Example Questions
Example Question #1 : Evaluating And Simplifying Expressions
Half of one hundred divided by five and multiplied by one-tenth is __________.
1
5
2
1/2
10
1
Let's take this step by step. "Half of one hundred" is 100/2 = 50. Then "half of one hundred divided by five" is 50/5 = 10. "Multiplied by one-tenth" really is the same as dividing by ten, so the last step gives us 10/10 = 1.
Example Question #2 : Evaluating And Simplifying Expressions
A total of 150 million votes were tallied in a presidential election. Votes were cast for either Hillary Clinton, Rand Paul, Al Gore, or Gary Johnson. If Clinton received 3 times the number of votes as Johnson, Paul received 30% of the vote, and Gore receieved 30 million total votes, who received the most votes in the election?
Hillary Clinton
Gary Johnson
Al Gore
Rand Paul
Hillary Clinton
There are a few ways to do this problem, but we will focus on the total number of votes method as follows. First, let Clinton = C, Gore = G, Paul = P, and Johnson = J. We know C + G + P + J = 150 million. We also know that C = 3J. Paul received 30% of the vote which is 150,000,000 * .3 = 45 million votes. Gore received 30 million votes. We can now create an equation with individual totals and substitute 3J for Clinton's vote total:
3J + 30 million + 45 million + J = 150 million
4J = 75 million
J = 18.75 million
Then C = 3J = 56.25 million. So Clinton received 56.25 million votes, Paul received 45 million votes, Gore received 30 million votes, and Johnson received 18.75 million votes. The correct answer is Hillary Clinton.
Example Question #3 : Evaluating And Simplifying Expressions
Justin makes 61.9% of his free throws. During the season he had 84 free throw attempts. How many of Jason’s shots did not go in?
40
32
36
52
21
32
Find how many free throws Justin made: 84 x 0.619 = 51.99. Since the problem talks free throws, we round to 52 shots went in. To calculate shots missed:
84 – 52 = 32.
Example Question #3 : Evaluating And Simplifying Expressions
If 5x + 30 = 6 – 7x, then x = ?
x = –37
x = –2
x = –18
x = 2
x = –10
x = –2
Combine like terms by subtracting 6 from both sides so: 5x + 24 = –7x. Then subtract 5x from both sides: 24 = –12x. Divide both sides by –12 and x = –2.
Example Question #4 : Evaluating Expressions
If ab - bc + d = d2 - c2, then what is the value of a when b is two, c is negative one, and d is zero?
ab - bc + d = d2 - c2
We need to substitute values in for b, c, and d, and then solve the equation for a.
a(2) - 2(-1) + 0 = 02 - (-1)2
2a +2 + 0 = 0 - (1)
2a + 2 = -1
2a = -3
a = -3/2
The answer is -3/2.
Example Question #2 : How To Evaluate Algebraic Expressions
If 11x + 4 = 19x – 12, then what is 2x – 4?
2
Not possible
4
0
–8
0
First solve for x. The first equation would simplify as:
16 = 8x
x = 2
If we plug x = 2 into the second expression:
2(2) – 4 = 0
0 is the correct answer.
Example Question #4 : Evaluating And Simplifying Expressions
If x = 2 and y = 3, then evaluate 2(x – 3) + 5y2
49
52
43
37
62
43
To evaluate an expression we make substitutions into the expression
2(x – 3) + 5y2 becomes 2(2 – 3) + 5 * 32 = –2 + 45 = 43
Example Question #5 : How To Evaluate Algebraic Expressions
IF 5x3 = 40, then what is the value of 12x – (x/2)?
24
10
23
17
33
23
Use the first equation to solve for x, then plug into the 2nd equation to find a value.
5x3 = 40
x3 = 8
x = 2
12(2) – (2/2) = 24 – 1 = 23
Example Question #3 : How To Evaluate Algebraic Expressions
A rowing team paddles upstream at a rate of 10 miles every 2 hours and downstream at a rate of 27 miles every 3 hours. Assuming they are paddling at the same rate up and downstream, what is the speed of the water?
5
1
Cannot be determined
7
2
2
Upstream: p – w = (10/2) or p – w = 5 miles/hour
Downstream: p + w = (27/3) or p + w = 9 miles/hour
Then we add the two equations together to cancel out the w's. After adding we see
2p = 14
p = 7 miles/hour where p is the rate of the paddling. We plug p into the equation to find
w = 2 miles/hour where w is the rate of the stream's water.
Example Question #1 : How To Evaluate Algebraic Expressions
Tim is two years older than his twin sisters, Rachel and Claire. The sum of their ages is 65. How old is Tim?
21
20
24
23
22
23
The answer is 23.
Since Rachel and Claire are twins they are the same age. We will use the variable r to represent both Rachel and Claire's ages.
From the question we can form two equations. They are:
t = r + 2 and 65 = t + 2r
lets plug the first equation into the second to solve for r.
65 = (r + 2) + 2r
65 = 3r +2
63 = 3r
r = 21 This means Rachel and Claire are 21 years old. Plug this into the equation so
t = 23 Tim is 23 years old.