To solve this equation, we first need to simplify the left side of the equation:

1/4:3/4 x - 1/2 + 2/5 = 1/2
1/4 x - 3/8 + 2/5 = 1/2
1/4 x - 3/8 + 16/40 = 20/40
1/4 x - 3/8 + 16/40 = 1/2

Next, we need to find a common denominator for the fractions on the left side:

1/4 x - 3/8 + 16/40 = 1/2
10/40 x - 15/40 + 16/40 = 20/40
(10x - 15 + 16) / 40 = 20/40
(10x + 1) / 40 = 20/40

Now we can solve for x by multiplying both sides by 40:

10x + 1 = 20
10x = 19
x = 19/10

Therefore, the solution to the equation is x = 19/10.