It is indeed .40, or just 0.4.
For reference, if you ever needed to know how to convert from fractions to decimals for other decimals, follow this procedure:
1.) Multiply/Divide both the numerator and denominator by a number such that the denominator will equal to 100.
So for 2/5, we can identify that 5 is the denominator. In order to find out what number we need to multiply to 5, we can divide 100 by 5, which will give 20.
So, 2/5 = (2 * 20)/(5 * 20) = 40/100.
2.) Completely ignore the denominator.
It might sound silly, but just pretend the 100 isn't there. For now. You'll see why in just a second.
3.) Move the decimal point of the number TWO PLACES to the LEFT.
So the decimal point in 40 is right after the zero. Moving it two places to the left will bring the decimal point right before the 4, making the answer 0.4.