<human>:  Leticia, Scarlett, and Percy decide to eat at a Greek restaurant for lunch. The prices for their dishes cost $10, $13, and $17, respectively. If the trio gives the waiter a 10% tip, how much gratuity should the waiter receive in dollars?
<bot>: How much does the bill cost? ** The total bill comes to $10 + $13 + $17 = $<<10+13+17=40>>40.
How much gratuity does the waiter earn? ** The total gratuity earned comes to $40 * 0.1 = $<<40*0.1=4>>4
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