Answer:
$1.60
Explanation:
We can create an equation to solve for the original bill. First we can set the unknown value--the original bill--to x.
2.50x = 4
We multiply that bill (x) by 250% (2.50) and set that equal to the tip. (Since the tip he gave is over 1, we can assume that Aaron gave more than he paid for the coffee)
Then we divide by 2.50 on both sides.
x = 1.6
Therefore, the original bill was for $1.60. Aaron gave 250% more of that, which is $4. Aaron is a nice guy!