Answer:
40
Step-by-step explanation:
In word problems, the word "of" usually means multiply. Thus, for example, 10% of $50 is $5. This is because we can write 10% as 0.10 or as 10/100 (which is 1/10) and then multiply: (1/10)(50) = 5
So, we often see equations like:
R = (1/2)D meaning R is 50% of D, or R is half of D
Let x = the number we want to find
This problem says:
"12 is 30% of what number?"
12 = (30/100) * x
12 = (3/10)x
(10/3)12 = x [multiply both sides by (10/3)]
40 = x
Checking (very important):
Is 12 = (3/10)(40) ?
12 = (3)(4) ?
12 = 12 ? yes
