Which of the following expressions could give the total amount of a $45 restaurant bill with a 15% tip added on?

everyone is saying the answer is (1.15)($45) but i do not know how this is the case. i do know that you have to do 0.15x45 but i don't know how they got 1. explain?

$51.75

Step-by-step explanation:

Given

Total amount of bill, x= $45

Tip Percent=15%

⇒15% on $45 is to be paid extra as tip, other than the already paying $45

⇒Tip

So total amount to be paid= Bill+ tip

=$51.75

i dont know nkw

step-by-step explanation:

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(0.2)+(-8)=0.3+-3+0.3m is the equation i guess? ?

step-by-step explanation: