Answer:
$15
Explanation:
20% = 20/100 = 0.2
40% = 40/100 = 0.4
20% of $30 = 0.2 x 30 = $6
If 40% of some P = $6 then
0.4 x P = $6
P = 6/0.4 = $15
We can also figure this out intuitively:
Since the percentage is doubled, the amount must be halved for both percentage amounts to be the same; 30/1 = 15