40 minutes*7 days of the week= 280 minutes a week. So, 320-280= 40 minutes left over. 40:320= 1:8. You were correct!
Answer:
Part A: 60
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60.
12, 24, 36, 48, 60.
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Part B: 9
81 / 72 = 9
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Part C: 9 (8 + 9)
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GCF of 72 and 81 is 9...
Divide 72 by 9 and get 8.
Divide 81 by 9 and get 9.
To check multiply 9 with 8, and multiply 9 by 9.
20 = 40e^-0.1446t
e^-0.1446t = 0.5
t = ln 0.5 / -0.1446
t = 4.8 days