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Answer:

So then the correct answer on this case would be:
D) decreases by 10.
Explanation:
For this case we assume that we have a linear model given by this expression:

Where m is the slope on this case m=6 and b the intercept.
So our model is given by: 
We want to see that if we decrease the value of y on 60 units what would be the change on the x axis.
Let's assume that we have two points
and 
If we find the differences between those points we got:

And we can rewrite this like that:

And if we know that
then we can solve
like this:

So then the correct answer on this case would be:
D) decreases by 10.
Answer:
=$4.07 unit
Explanation:
<em>Weighted average contribution margin is applicable where a business sells more than one product in a constant mix or proportion. It gives an idea of how much is made on the average as contribution from th sale of a unit.</em>
It is determined as follows
Step 1
<em>Total contribution from a mix and total units</em>
<em>Total contribution from a mix</em>=(2500 × $3.50) + (2,000 × $4.80)
=$18,350
<em>Total units in a mix</em> = 2,500+ 2,000 = 4,500 units
Step 2
<em>weighted average unit contribution</em>
=$18,350/4,500units
=$4.07 unit