Question

Mike paid 2.94 in sales tax on an item that cost 42.00 before tax. At that rate how much would he pay in sales tax for an item that cost 58.00 before tax

Answer 1

$4.06 in sales tax before tax for $58
7% of $42 = 2.94
7% of $58 = 4.06

Answer 2

First we should find the percentage of the tax for the items Mike bought :
$\frac{42}{100} = \frac{2.94}{x} \\ x = \frac{2.94 \times 100}{42} = \frac{294}{42} = 7$
the tax of the items are 7% of the price
so we find this percent for 58
$\frac{58}{100} = \frac{x}{7} \\ x = \frac{7 \times 58}{100} = \frac{406}{100} = 4.06$
so now you can add the tax to the price:
$58 + 4.06 = 62.06$
hope you understand it
good luck