# SAT Math : How to find percentage

## Example Questions

### Example Question #11 : How To Find Percentage

What number is 30% of 90?

Explanation:

Verbal cues include "is" and "of."  "Is" means equals and "of" means multiplication.

So the equation to solve becomes

### Example Question #11 : How To Find Percentage

If the length of a rectangle is increased by 50% and with width of the same rectangle is decreased by 50%, what is the effect on the area of the rectangle?

It is unchanged

It is increased by 50%

It is increased by 25%

It is decreased by 50%

It is decreaed by 25%

It is decreaed by 25%

Explanation:

This is a good question to use random numbers. Lets use 100 and 10 as the lengths. That means the area = 100 x 10 = 1000

If we increase the length of the side measuring 100 by 50% = 150

If we decrease the length of the other side 50% = 5

Area = 150 x 5 = 750

We see that the area decreased by 250 or 25% decrease in area!

### Example Question #13 : How To Find Percentage

If 80 percent of x is 200, what is 60 percent x?

175

200

150

250

225

150

Explanation:

### Example Question #14 : How To Find Percentage

Seventeen percent of some number is 34. What is this number?

Explanation:

The algebraic expression is:

### Example Question #12 : How To Find Percentage

What number is 125% of 60?

75

80

66

90

60

75

Explanation:

Translate this into a mathematical equation:

x = 1.25 * 60

x = 75

### Example Question #13 : How To Find Percentage

If 10% of  is equal to 25% of , and , what is the value of ?

Explanation:

Find 25% of :

10% of  is equal to 4. Therefore, .

Divide both sides by 0.1 to find that .

### Example Question #11 : Fractions

There are  registered students in the math club. Students are deciding what activity they could do for their end of semester event. They have three choices: rock climbing, bowling, or outdoor laser tag.  students vote for rock climbing,  students vote for bowling, and  students vote for outdoor laser tag.

What percent of students did not vote?

Explanation:

The number of students who did not vote is:

The percent of students who did not vote is therefore:

of the students did not vote.

### Example Question #1161 : Sat Mathematics

Joaquin is running for Prom King.  If he receives  of the votes from a senior class of  students, and  of the votes from a junior class of  students, how many votes did he receive in total?

Explanation:

First, we find how many seniors voted for him:

0.30 * 200 = 60 seniors

Then we find how many juniors using the same method

0.60 * 250 = 150 Juniors

Finally, we add the two together

60 + 150 = 210 students total

### Example Question #11 : Other Percentage

13 is what percent of 25?

Explanation:

To solve this problem, we should set up the following proportion

where x is the percentage we are looking for.

To solve, simply cross multiply and solve for x.

### Example Question #13 : Other Percentage

What percent of  is