GRE Quantitative Reasoning › How to express a fraction as a ratio
Abe, Bob, and Carol went to lunch together and their total bill was 60 dollars. They first decided to split the bill , respectively. Unfortunately, Abe was short on cash and they decided to split the bill
. How much more did Carol have to spend on the under the new system of splitting the bill?
Since the problem is focusing on Carol, we will only worry about Carol's contribution to the bill.
The original split on the bill was with Carol paying the smaller portion. With
parts, each one was
. This was originally the amount Carol was responsible for.
With the the ratio of , this meant there are
parts with each being
. Carol pays instead
.
The difference is then or
.
If Jill, Jack and John found and decided to split it
respectively, how much more did Jack get than John?
If Jill, Jack and John get , that means there are
parts.
Because they found , each part gets
or
.
Jack gets or
.
John gets or
.
Since the question is asking how much more did Jack get than John, we subtract and
to get
.
If the ratio of girls to boys is , what could be the number of children in the class?
If there are girls and
boys, that means we have
students in the class. To continue to have this ratio, we need an answer than is a multiple of
.
is a multiple of
which is the right answer.
A used car lot has total vehicles to be sold.
of the vehicles are 4-wheel drive and the rest are 2-wheel drive. What is the ratio of 2-wheel drive to 4-wheel drive vehicles on the lot?
27 of the 72 cars are 4-wheel drive, we can write this as a proportion.
The proportion of the 4-wheel drive cars to the total number of vehicles.
Therefore, to find the proportion of 2-wheel drive cars is,
Therefore the ratio of 2-wheel drive:4-wheel drive vehicles is 5:3.
If there are dolls and
of them are not broken, what's the ratio of broken dolls to unbroken dolls?
You don't need to solve for the actual number of broken or unbroken dolls. Instead, put the percentages in the ratio because no matter what, the percentages are fixed regardless of amount of dolls broken or unbroken.
So the question is asking for broken to unbroken. The percentage of broken dolls is .
So we have a ratio of or
.
There are philosophy books and
history books on a shelf. The number of philosophy books is doubled. What is the ratio of philosophy books to history books after this?
First, compute the new number of philosophy books. This will be .
The ratio of philosophy books to history books is thus:
This can be reduced by dividing the numerator and the denominator by :
Therefore, the ratio is .
On a desk, there are papers for every
paper clips and
papers for every
greeting card. What is the ratio of paper clips to total items on the desk?
Begin by making your life easier: presume that there are papers on the desk. Immediately, we know that there are
paper clips. Now, if there are
papers, you know that there also must be
greeting cards. Technically you figure this out by using the ratio:
By cross-multiplying you get:
Solving for , you clearly get
.
(Many students will likely see this fact without doing the algebra, however. The numbers are rather simple.)
Now, this means that our desk has on it:
papers
paper clips
greeting cards
Therefore, you have total items. Based on this, your ratio of paper clips to total items is:
, which is the same as
.
If there are fifteen girls and six boys in a class, what is the ratio of boys to girls?
Let's convert the words into numbers. Since there are girls and
boys, we need ratio of boys to girls. The ratio should be
.
Express as an integer ratio.
To find an integer ratio, let's find the fractions with a common denominator. This will be . Then, we multiply the left by
and the right by
to get fractions of
and
. With the same denominators, we just have numerators to compare. Ratio is then
.
Express as a ratio.
A ratio is two numbers separated by a colon. When expressing fractions as a ratio, the numerator is the number to the left of the colon while the denominator is to the right of the colon. The answer is