All SAT Math Resources
Example Questions
Example Question #41 : Percentage
is of what number?
None of the given answers are correct.
To solve this problem, we can set up a proportion and solve for our missing value using cross multiplication.
Example Question #211 : Arithmetic
is of what number?
Don't let the pi throw you off on this question. We can set up a proportion to solve for the whole that we are looking for.
(Remember that any percentage can also be written as a fraction.)
Now we can solve for our unknown by using cross multiplication.
Therefore, is of .
Example Question #42 : Percentage
is of what number?
We can set up a proportion to solve this problem. Remember that we can express percentages as fractions.
Now we can cross-multiply and solve for our unknown.
Example Question #1091 : Sat Mathematics
55 and 1/2% of 23 is about what?
11
155
49
2
13
13
55 and 1/2% can be written as a decimal: 0.555. To see what number is about 55.5% of 23, multiply 0.555 by 23. Answer: 12.765 or about 13.
Another route is to say that 55.5% is about half of 23. Half of 23 is 11.5. Since 55.5% is greater than 50%, 13 is the logical choice instead of 11.
Example Question #2 : How To Find Decimal Equivalent To A Percentage
Let x and y be numbers such that x and y are both nonzero, and x > y. If half of x is equal to thirty percent of the positive difference between x and y, then what is the ratio of x to y?
–2/3
2/3
–3/2
–1
3/2
–3/2
We need to find expressions for fifty percent of x and for thirty percent of the positive difference between x and y. Then, we can set these two expressions equal to each other and determine the ratio of x to y.
Fifty percent of x is equal to one-half of x, which is the same as multiplying x by 0.50.
50% of x = 0.5x
Thirty percent of the positive difference between x and y means that we need to multiply the positive difference between x and y by thirty percent. Because x > y, the positive difference between x and y is equal to x – y. We then need to take thirty percent of the quantity x – y. Remember that to convert from a percent to a decimal, we move the decimal two spaces to the left. Therefore, 30% = 0.30. We can now multiply this by (x – y).
30% of x – y = 0.30(x – y)
Now, we set the two expressions equal to one another.
0.5x = 0.30(x – y)
Distribute the right side.
0.5x = 0.3x – 0.3y
The ratio of x to y is represent by x/y. Thus, we want to group the x and y terms on opposite sides of the equations, and then divide both sides by y.
0.5x = 0.3x – 0.3y
Subtract 0.3x from both sides.
0.2x = –0.3y
Divide both sides by 0.2
x = (–0.3/0.2)y
Divide both sides by y to find x/y.
x/y = (–0.3/0.2) = –1.5.
Because the answers are in fractions, we want to rewrite –1.5 as a fraction. We can write –1.5 as –1.5/1 and then mutiply the top and bottom by 2.
(–1.5/1)(2/2) = –3/2
The answer is –3/2
Example Question #1 : How To Find Decimal Equivalent To A Percentage
If of is equal to of , and of is equal to of , then what percent of is ?
25
125
100
75
133
75
We are told that 50% of x is equal to 25% of y. We need to represent these two pieces of information as algebraic expressions. We can convert 50% and 25% to decimals by moving the decimals two places to the left. Thus, 50% = 0.50, and 25% = 0.25. To find 50% of x, we multiply x by 0.50. In other words, 50% of x = 0.50x. Likewise, 25% of y = 0.25y. We now set 0.50x and 0.25y equal to one another.
0.50x = 0.25y
Let's divide both sides by 0.25 to get rid of decimals.
2x = y
Next, we are told that 40% of y is equal to 60% of z. We will represent 40% and 60% as 0.40 and 0.60, respectively. Thus, we can write the following equation:
0.40y = 0.60z
Ultimately, we are asked to find x as a percentage of z. This means we want to find an equation with x and z, but not y. If we solve for y in the second equation, and then substitute this value into the first, we can eliminate y.
Let's take the equation 0.40y = 0.60z and divide both sides by 0.40.
y = 1.5z
Now, we can take 1.5z and substitute this for y in the first equation.
2x = 1.5z
In order to find x as a percent of z, we must solve for x in terms of z. This means we must divide both sides of the equation by 2.
x = 0.75z
x is 0.75 times z. We can represent 0.75 as 75%, because in order to convert from a decimal to a percent, we need to move the decimal two spaces to the right. Therefore, if x = 0.75z, then x = 75% of z.
The answer is 75.
Example Question #4 : How To Find Decimal Equivalent To A Percentage
What is in decimal form?
The correct answer is .
This can be obtained by taking the percentage of and dividing by .
This shifts the decimal place over two places to the left, which results in as the decimal of .
Example Question #1 : How To Find Decimal Equivalent To A Percentage
Find the decimal equivalent to the percentage:
In order to find the decimal equivalent of a percentage, the number that makes up the percent has to be divided by 100. However, since it is division by a power of 10, we can accomplish the same thing, by moving the decimal point 2 places to the left, thus making the number smaller. For this problem, that looks like this:
Example Question #1 : Decimals And Percentage
Find the decimal equivalent to the percentage:
In order to find the decimal equivalent of a percentage, the number that makes up the percent has to be divided by 100. However, since it is division by a power of 10, we can accomplish the same thing, by moving the decimal point 2 places to the left, thus making the number smaller. For this problem, that looks like this:
Example Question #2 : How To Find Decimal Equivalent To A Percentage
Find the decimal equivalent to the percentage:
In order to find the decimal equivalent of a percentage, the number that makes up the percent has to be divided by 100. However, since it is division by a power of 10, we can accomplish the same thing, by moving the decimal point 2 places to the left, thus making the number smaller. For this problem, that looks like this: