Question

Please help with these

Answer 1

Set up a proportion.


`(3~minutes)/(2~questions)` =
`(x~minutes)/(12~questions)`

Cross multiply.

2x=36
x=12

It would take her 12 minutes.

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Formula for surface area of a cube: 6a² where a=20.

6 x (20)²
6 x 400
= 2400

Surface area: 2400 cm

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Mean absolute deviation: The average distance from each number in the set to the mean of the set.

Mean of the set:
`((3+8+10+12+15))/(5) = (48)/(5) = 9.6`

9.6-3=6.6
9.6-8=1.6
10-9.6=0.4
12-9.6=11.4
15-9.6=5.4

Mean of 6.6, 1.6, 0.4, 11.4, and 5.4:
`((6.6+1.6+0.4+11.4+5.4))/(5) = (25.4)/(5) = 5.08`