All ISEE Lower Level Quantitative Resources
Example Questions
Example Question #11 : Ratio And Proportion
In a litter of puppies, there are black puppies and white puppies. What is the ratio of the number of white puppies to black puppies?
The ratio wants us to compare the number of white puppies to the number of black puppies.
We can say the ratio of white puppies to black puppies is . When we write that as a fraction, it becomes , so we can also say that the ratio of white puppies to black puppies is or .
Example Question #11 : Ratio And Proportion
Stacy has started collecting coins. She has twice as many wheat pennies as she does dimes, and three times as many quarters as she does dimes. If Stacy has dimes, what is the ratio of wheat pennies to quarters?
We know that Stacy has 1946 dimes.
We also know that she has twice as many wheat pennies, so we must multiply by to find the total number of wheat pennies.
We also know that Stacy has three times as many 1986 quarters, so we multiply by to find the total number of 1986 quarters.
Now our ratio of wheat pennies to 1986 quarters is , but this can be simplified because both numbers are divisible by .
So our ratio becomes
Example Question #11 : Ratio And Proportion
A recipe calls for of a cup of flour and of a cup of sugar. How many cups of sugar and flour combined does the recipe call for?
Add .
Since both of these fractions have the same denominator, we just rewrite 3 on the bottom. When you add fractions, then add straight across the top, .
This gives us .
We can turn this into a mixed number by dividing with a remainder of 1. We place the orginal one as our whole number, and the remainder over the 3 for the fraction, .
Example Question #13 : Ratio And Proportion
Which fraction is the greatest?
As the denominator gets bigger, the fractions gets smaller, so when looking for the largest fraction, we are looking for one with the highest numerator and the lowest denominator. In this case, has the largest numerator and the smallest denominator.
Example Question #14 : Ratio And Proportion
A foot tree casts a shadow of feet. How long is the shadow of a nearby foot tall building if the tree and its shadow are in the same ratio as the building and its shadow?
To solve this, I need to set up a proportion, and then solve algebraically.
feet, the height of the tree, is equivalent in our proportion to feet, the building's height.
feet, the tree's shadow, is equivalent in our proportion to , the building's shadow.
Cross-multiply:
Divide each side by :
Example Question #15 : Ratio And Proportion
There are 18 tea bags in a box. Beth uses 2 tea bags, Brad uses 1 tea bag, and Joe uses 1 tea bag. What fraction of the tea bags now remain?
If there are 18 tea bags in a box and Beth uses 2 tea bags, Brad uses 1 tea bag, and Joe uses 1 tea bag, then 14 tea bags will remain.
Given that , the correct answer is .
Example Question #16 : Ratio And Proportion
If Katie's computer has 60% of its power left after being on for 2 hours, how many hours of battery power remain?
If Katie's computer has 60% of its power left after being on for 2 hours, then that means 40% of the battery was used to power the 2 hours. X represents the total number of hours that the battery can last.
Next, we divide each side of the equation by 40. This results in:
.
Since 60% of 5 is equal to 3, the correct answer is 3.
Example Question #17 : Ratio And Proportion
Marcus is 9 years old. He has been playing soccer for 3 years. If he plays soccer for a 4th year, for what proportion of his life will he have played soccer?
If Marcus is 9 years old and has been playing soccer for 3 years, he will be 10 years old during his 4th year. He has therefore played soccer for 4 out of 10 years, or
of his life.
Example Question #18 : Ratio And Proportion
Ralph watched of a movie that is 2 hours and 8 minutes long. How much of the movie did he watch (in minutes)?
The first step is to convert the length of the movie from hours to minutes. A movie that is 2 hours and 8 minutes long is 128 minutes long.
128 divided by 16 is 8. Therefore, 8 minutes is of the movie.
Example Question #19 : Ratio And Proportion
If 5 out of 20 students in a class have green eyes, what percentage of students have green eyes?
Percentages are fractions out of 100, so the way to solve the problem is to have the denominator be 100. In order to do this we must multiply 20 by 5 in order to get 100.
If we multiply the denominator by 5, we must do the same to the numerator.
When we do this, we are left with which is 25%
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