Use concept of multiples to solve SAT Math Ratio questions

By using this SAT Math strategy you basically multiply given number(s) by some unknown number to reach the target. You can use either hit and trial method or divide target number by given number. It is illustrated in following example.

Example

A box contains 90 buttons, some blue and some white. The ratio of the number of blue to white buttons is 12:6. How many of each color button is in the box?

Solution

We know there is a ratio of 12 blue buttons to every 6 white buttons. This means that for every batch of 12 buttons in the box there is also a batch of 6 buttons. We also know there is a total of 90 buttons. This means that we must determine how many batches of blue and white buttons add up to a total of 90. So let’s write an equation:

12x + 6x = 90, where x is the number of batches of buttons
18x = 90
x = 5

So we know that there are 5 batches of buttons.

Three steps approach:

In such SAT Math Ratio questions

• add up both numbers of ratio (12+6) and
• divide the target/ total value (90) by this (18)
• mutiply each ratio number by this answer.

Therefore, there are (5 x 12) = 60 blue buttons and (5 x 6) = 30 white buttons.