Answer:
just add 8+8+8 until you get to the number u want/need and the same with 7. Or you can multiply.
8x1=8
7x1=7
8x3=24 (8+8+8=24)
7x3=21 (7+7+7=21)
etc.
Hope it helps!
Answer:

Step-by-step explanation:
Given
--- scale factor
Required [missing from the question]:
The ratio of width of the model to the original
From the question, we understand that the scale factor is: 2 : 15
The ratio of the width of the model to the original equals the given scale factor i.e.

At 95% confidence interval, true population mean is given by
x+/- 2sd
where x= sample mean and sd = sample standard deviation
True mean of population = 13.50 +/- 2*1.51 = 13.50+/-3.02
Interval: 13.50+3.02, 13.50-3.02 = 16.51, 10.48