40% of the airplanes were hydroplanes.
If 660 were hydroplanes, how many were not hydroplanes?
SOLUTION
If 40% of the airplanes were hydroplanes.
Let x represents the total number of Hydroplanes.
So that 40 % of X = 660
40/ 100 x X = 660
2 / 5 x X = 660
2X / 5 = 660
cross- multiply, we have:
2X = 660 X 5
2 X = 3300
Divide oth sides by 2 , we have :
X = 3300 / 2
X = 1650
Total number of Hydrophones = 1650
Those that are Hydrophones = 660
Those that are not Hydrophones = 1650 - 660
= 990