Answer:
50.1 deg F
Step-by-step explanation:
1.6deg F for every 1,000ft. You need to get to 9,000ft. 1.6degx9=14.4
64.5deg-14.4deg=50.1degF
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Some of the prime factors are 1,2,4,5,10,20,-1,-.2,-4,-5,-10,-20, and since 5 is prime you can just start with 5 and 4