Restaurant bill amount excluding tip = $16.
Tip is 18% of the billed amount.
18% can be written in decimal form as 0.18.
18% of 16 = 0.18 × 16.
Total amount including tip amount = 16 + 0.18 × 16.
Factoring out 16, we get
16(1+0.18).
We can see we get same expression in first option.
Therefore, (1+0.18)16 expression is equivalent to the amount Miko paid.
