12.65+21.55=34.20
34.20*.15=5.13
.15 is the percentage of the tip they pay in decimal form in order to multiply it on a calculator.
Answer is $5.13
You want to multiply together the number of possible choices for each digit in the code.
0-9 is ten possible numbers, since repetitions are allowed (example code 2,2,2,2) there are ten possible choices per digit in the code.
10*10*10*10 = 10,000 four digit coded possible
The answer is the 3rd choice. The beginning temperature is -9 so you add the 7 to the -9 degrees to find the temperature at noon because it increased.
