Question 110436
let x=1+decimal of the tax.
7.85x=8.3
7.85x/7.85=8.3/7.85
x= 1.057
tax=(1.057-1)*100
=.057*100
5.7%
.
To calculate a 15% tip on 8.30:
move the decimal point one to the left (.83) and add 1/2 the result to the result. .83+.41=1.24 est.
Be a big spender and give $1.25
Ed