In one month holly earned $800 at her part-time job, and $50 was withheld for federal income tax. suppose she earns $1200 next month. how much will be withheld for federal income tax? round the answer to the nearest dollar.

In one month, Holly earned $800. From those $800, 50 dollars were withheld for federal income tax.
We suppose that next month, she earns $1200. Let x be the amount withheld for federal income tax, in dollars. We'll use the rule of three.

$800 ---> $50
$1200 ---> x

x = (1200*50) / 800
x = 60 000 / 800
x = 75

So next month, 75 dollars out of 1200 will be withheld for federal income tax.
Hope this helps! :)