Question 37·Easy·Percentages
In a recent survey of 800 adults, 560 said they preferred coffee over tea. What percentage of the surveyed adults preferred coffee?
For questions asking what percentage one quantity is of another, always form the fraction first. Simplify the fraction if possible, then convert it to a decimal and multiply by 100 to get a percent. As a quick reasonableness check, compare your result to familiar benchmarks like 50% (half) and 75% (three-quarters) based on how large the part is relative to the whole.
Hints
Set up the fraction
Ask yourself: what fraction of the total 800 adults preferred coffee if 560 did? Write that as a fraction with 560 on top and 800 on the bottom.
Simplify the fraction
Once you have the fraction, see if you can divide the top and bottom by the same number to make the numbers smaller. Both 560 and 800 end in a 0—what does that tell you?
Turn the fraction into a percent
After simplifying, convert the fraction to a decimal, then multiply by 100 to get a percentage. Remember that 1/10 is 10%, 1/2 is 50%, and 3/4 is 75%; use these to check if your answer is reasonable.
Desmos Guide
Use Desmos to compute the percentage
In Desmos, type 560/800*100 and look at the numeric result; that value is the percentage of surveyed adults who preferred coffee.
Step-by-step Explanation
Identify the part and the whole
The question asks for the percentage of surveyed adults who preferred coffee.
- Part (number who preferred coffee): 560
- Whole (total surveyed): 800
So we are finding what percent 560 is out of 800.
Write and simplify the fraction
Turn the situation into a fraction:
Now simplify this fraction. Both 560 and 800 are divisible by 80:
So simplifies to .
Convert the fraction to a percentage
A percentage is a fraction out of 100. The fraction is equal to the decimal .
To convert a decimal to a percent, multiply by 100:
So out of is 70%, which corresponds to choice C.