If , what is the value of ?
This is a ratio problem. What do we know?
We know that 24 to 15 (24:15) is equal to 4 to n (4:n)
What are we looking for? What is 4 times n or 4n.
Several ways to find:
4 to n is the same as 16 to 4n (expand both top and bottom by 4).
24 to 15 has a common factor of 3 – it is the same as 8 to 5
We can rewrite as 8/5=16/(4n)
Cross multiplying gives:
8 times (4n) = 16 times 5
Divide both sides by 8
(4n)= 16*5/8 or 16/8 * 5 = 2*5 = 10
Another way find the value of n first and then multiply by 4.
The third option is to plug in, but in this case since we have n in the equation and (4n) as the answer it is not as an appealing option as in other questions.
Note that the answer on the SAT website follows a correct calculation but marked the wrong answer as the correct one. Don’t be alarmed – this only shows there are humans on the other side of the exam !