Alright, lets get started.
We are asked, what decimal part of 420 is 147.
Lets suppose say x part of 420 is 147.
It means we could write it in equation, so
[tex] 420 * x = 147 [/tex]
Dividing 420 in both sides of the equation, so next step would be
[tex] \frac{420*x}{420}=\frac{147}{420} [/tex]
[tex] x =\frac{147}{420} [/tex]
x = 0.35
Hence 0.35 decimal part of 420 is 147.
So the answer is 0.35. : Answer
Hope it will help :)