You have the right answer but for the second part it's 65+10/5=x
Answer:

Step-by-step explanation:
The Fundamental Theorem of Calculus states that:
![\displaystyle \frac{d}{dx}\left[ \int_a^x f(t)\, dt \right] = f(x)](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7Bd%7D%7Bdx%7D%5Cleft%5B%20%5Cint_a%5Ex%20f%28t%29%5C%2C%20dt%20%20%5Cright%5D%20%3D%20f%28x%29)
Where <em>a</em> is some constant.
We can let:

By substitution:

Taking the derivative of both sides results in:
![\displaystyle g'(s) = \frac{d}{ds}\left[ \int_6^s g(t)\, dt\right]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20g%27%28s%29%20%3D%20%5Cfrac%7Bd%7D%7Bds%7D%5Cleft%5B%20%5Cint_6%5Es%20g%28t%29%5C%2C%20dt%5Cright%5D)
Hence, by the Fundamental Theorem:

I'm tentatively changing my answer to say this kind of relies on practical knowledge of how stores tend to operate. If 20 coupons are given out, the store has sold all 500 shirts, arguably at a loss to the retailer. They have to have more shirts in stock to be sold at full price because, well, that's how they make money. It's more likely that such a store would carry more than just 500 shirts at the start of each day, so A is (probably) wrong.
The first step is to find the CHANGE. This is done by subtracting the two values and taking the absolute value. Next step is to find the ratio of the change to the original and multiplying by 100% to make it a percentage.
So;
a) change = Ι60 - 25Ι = 35.
ratio of change to original = 35:25,
multiplying by 100% will give 35/25 × 100% = 140%.
Hence it is a 140% INCREASE.
b) change = | 30 - 66 | = 36
the ratio is 36:66
multiplying by 100% = 36/66 × 100% = 0.545454... ×100% ≈ 54.5%
Hence it is a 54.5% DECREASE.
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