Determine the compound formula if mass fraction w (Cu) = 40% w (S) = 20% w (O) = 40%

Let us have 100
then given a percentage .:
m (Cu) = 40 g
m (S) = 20 g
m (O) = 40 g
Let’s find the amount of substance for each element:
n (Cu) = 40/64 = 0.625 mol
n (S) = 20/32 = 0.625 mol
n (O) = 40/16 = 2.5 mol
We have obtained the following ratio:
0.625: 0.625: 2.5
Divide everything by 0.625
1: 1: 4
Then
CuSO4 copper sulfate 2