Answer:
The constant of variation is 5.
Step-by-step explanation:
In direct variation, as y varies directly with x, the standard equation is
y = kx,
where k is the constant of variation.
In your case, we use R and S. R varies directly with S, so we have
R = kS
We know that when S = 16, R is 80, so we plug in those values and solve for k, the constant of variation.
R = kS
80 = k(16)
k = 80/16
k = 5
40 dollars they each spent 40 dollars from 70 dollars
The number of ways when the choice is not relevant is 4
<h3>How to determine the number of ways?</h3>
The number of colors are:
Colors, n = 4
The color to choose are:
r = 3
<u>Relevant choice</u>
When the choice is relevant, we have:

This gives

Evaluate
Ways = 24
Hence, the number of ways when the choice is relevant is 24
<u>Not relevant choice</u>
When the choice is not relevant, we have:

This gives

Evaluate
Ways = 4
Hence, the number of ways when the choice is not relevant is 4
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