Ratio
The ratio is basically comparing of two or more numbers or quantities with same units. While solving problems on ratio make sure that numbers are having same units. Like one number in kg and another number in liter cannot be compared, similarly one number in meter and number in dollars cannot be compared. For GRE you should be very cautious for the units. Ratio is written in terms of fraction, the upper number is numerator and bottom number is a denominator
As for example ; If a box is having 6 red balloons and 8 green balloons then the ratio of red balloons to green balloons in the box = 6/8
Ratio can be reduced to their lowest term; e.g. the above ratio can be written as = ¾
Expressing Ratio
Ratio can be expressed A : B or A to B or A/B
In Ratio order is important like ratio of girls to boys , men to women, oranges to apple , so in all these examples the first term will go as numerator and second term will go as denominator.
i.e.
Multiple Ratios
For comparing more than two quantities their interrelation is being considered as a : b : c : d.
1st and 3rd, 2nd and 4th are corresponding terms.
So, a/b = c/d; a is to b and c is to d.
Proportion
This is an equation for solving two ratios by cross multiplying it.
