The total bill for a dinner, before tax, is $40.00. if you leave a 15% tip, you will leave a tip of $?

$6.00

A fairly easy way to do the mental calculation of a 15% tip is to realize that ...

... 15% = 10% + (1/2)·10%

Of course, you can compute 10% by moving the decimal point 1 place left, so ...

... 10% of $40.00 = $4.00

Half that is $2.00, so the 15% tip is $4.00 +2.00 = $6.00.

y= -

y=x+9

?

step-by-step explanation: