Selection B is appropriate.
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It takes 12 times as long to fill the whole tank as it does to fill 1/12 of the tank.
.. 12 * (1/3 hour) = (1/3)*12 hour
Start with your lowest numbers, 3 bracelets have 24 beads. The easiest way to find your answer is to find out how many beads are on 1 bracelet. So 24/3 will give us that answer. 24/3=8. and then multiply 7 by 8 to get 56. then check your answer to make sure it fits.
3 x 8 = 24
5 x 8 = 40
7 x 8 = 56
9 x 8 = 72
Well, I would just reverse it. It seems you just have to reverse the whole problem.
Answer:
4.0
observed time spent exerciseing: 4.5
predicted time:5.5
residual: 1
5.0
observed time spent exerciseing: 6.5
predicted time:5.0
residual: 1.5
