Patrick took his parents to dinner and the bill was $70 plus 6% tax. if he left a tip of 15% of the total (food plus tax), what was the total cost of the dinner?

$85.33

Step-by-step explanation:

Bill: $70

Bill + Tax: $70 + $70(0.06)

              = $70 + $4.20

              = $74.20

Bill + Tax + Tip: $74.20 + $74.20(0.15)

                        = $74.20 + $11.13

                        = $85.33