Question 885960
A 5% sales tax on a $10 item is:
{{{ .05*10 = .5 }}} or $.50
After tax it casts $10.50
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The $10 item with a 30% discount 
before tax costs:
{{{ 10 - .3*10 = 10 - 3 }}}
{{{ 10 - .3*10 = 7 }}} or $7
and
{{{ 7 + .05*7 = 7 + .35 }}}
{{{ 7 + .05*7 = 7.35 }}} so 
the item costs $7.35 after tax
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As for what they want:
So, the sales tax before the discount
was $.50
The sales tax after the discount 
was $.35
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{{{ .5 - .35 = .15 }}}
The sales tax got reduced by $.15
Hope I got it