Question

he earned $60 income. 20% imposed on tax whats income now?

Answer 1

that is
60 - (60* 0.20)
or simply
60 * 0.80

Answer 2

really? i thought it would be 60*0.20?

Answer 3

Generally, when one earns money, tax is withheld from one's pay.
So, imagine you earn $60, but your employer is required by your State to deduct 20% of that as a tax. How much pay would you actually receive, in this case?

That's what @nincompoop is showing you in his/her comment, above.

Answer 4

He earned $60 income. 20% imposed on tax whats income now?

Ummm... Income is still $60.00 If it is all taxed away and a cow jumps over the moon, the income is still $60.00.

Perhaps a better question?