How to find the whole from the part with percentage - SSAT Middle Level Quantitative

The total number of plants has to be divisible by 3. Of the answer choices, the only one that is divisible by 3 is 18. You can check this because numbers that are divisible have the sum of their digits also divisible by 3. For example,

which is divisible by 3, so 18 is divisible by 3.

The answer multiplied by 24%, or, equivalently, 0.24, is 0.45. Subsequently, divide 0.45 by 0.24.

Taking of a number is the same as multiplying that number by . We can find our number, therefore, by dividing by :

330 is 75% of a number we will call ; alternatively, 0.75 multiplied by is equal to 330. Set up this equation and solve for :

is of a number we will call ; alternatively, multiplied by is equal to . Set up this equation and solve for :

We can rewrite % as 2.5%. 32 is 2.5% of a number , or, equivalently, 0.025 multiplied by a number is equal to 32. We can write this as an equation and solve for :

We can rewrite % as 12.5%. 88 is 12.5% of a number , or, equivalently, 0.125 multiplied by a number is equal to 88. We can write this as an equation and solve for :

3% of 5,319 can be calculated by multiplying 5,319 by 0.03, the decimal equivalent of 3%:

Multiply 5,319 by 3, then move the decimal point so that two digits are to the right:

,

so

Rounded to the nearest whole number, this is 160 signatures.

of the voters were unaffiliated, and were affiliated with other parties, so of the voters were registered as neither Republicans nor Democrats. Since of the voters numbered , we can find the total number of voters by setting up and solving a proportion:

which rounds to voters.

Set up the proportion statement and solve for by cross-multiplying:

Set up the proportion statement and solve for by cross-multiplying:

To determine what 60 percent of the number is, one must first determine what the number is. To find the number, set up a proportion relating the original percentage and the value of the percentage where the top number is the fractional value and the bottom number is the total.

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Use cross multiplication to solve for the number.

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Once the number is found, the new percentage can be found. There are two ways to do this: multiplication or a proportion.

• Multiplication:
• Proportion:

This means that 60 percent of the number is 66.

First, we need to determine the percentage of fish that are red. So add the percentages of blue and green fish and then subtract this number from 100. So,

and

If you notice that the problem already states how many fish constitute 25 percent, you don’t need to do any more work! Therefore, 50 fish are red.

The total number of plants has to be divisible by 3. Of the answer choices, the only one that is divisible by 3 is 18. You can check this because numbers that are divisible have the sum of their digits also divisible by 3. For example,

which is divisible by 3, so 18 is divisible by 3.

The answer multiplied by 24%, or, equivalently, 0.24, is 0.45. Subsequently, divide 0.45 by 0.24.

Taking of a number is the same as multiplying that number by . We can find our number, therefore, by dividing by :

330 is 75% of a number we will call ; alternatively, 0.75 multiplied by is equal to 330. Set up this equation and solve for :

is of a number we will call ; alternatively, multiplied by is equal to . Set up this equation and solve for :

We can rewrite % as 2.5%. 32 is 2.5% of a number , or, equivalently, 0.025 multiplied by a number is equal to 32. We can write this as an equation and solve for :