How do I do number 20

Answer:
I'm pretty sure he isn't being resonable because 15.75 plus tax, which is .08 or 0.10 cents, would be $16.
So let's do the math:
$16 x 3 = 48
And the gift card has $50 on it, so yeah he would have $2 to spare.
I hope this helps and please mark as brainliest!<3