X=18 and y=10 because they are both 90degree angles therefore all you have to do is solve the equations: 5x=90 and 9y=90.
There are 8! possible combinations, or 8p8, and there is only 1 that has them in order from oldest to youngest, so the answer is A.
Answer:
40 minutes
Step-by-step explanation:
12 envelopes every 10 minutes.
48 envelopes = 40 minutes
