What is the product of positive integers a and b such that 1 /a + 1 /b + 1 /ab = 1?

Step-by-step explanation:

Let your number be X. To increase X by 40% we can multiply it by 1.4, let's call this new number Y.

So Y = X * 1.4

Now to decrease Y by 40% we can multiply it by 1 - .4 = .6. Lets call this new number C.

So C = Y *.6 = (X * 1.4) * .6 = X * (1.4 * .6) = X * .84.

Therefore, C = .84 * X.

So we can see C is 84% of X, or 16% less than X.

Thus, if you increase a number by 40% then decrease it by 40%, the net percentage is -16% .