Answer:
![c[s(p)]=0.856p](https://img.qammunity.org/2017/formulas/mathematics/high-school/97vl0gybcssoa760eb4dufokork8eexcfh.png)
Explanation:
As per the statement:
Sarah is purchasing a shirt that is on sale for 20% off.
She knows the function that represents the sale price of her shirt is given by:
where, p is the original price of the shirt.
It is also given that:
She also knows she has to pay 7% sale's tax on the shirt. The cost of the shirt with tax is
c(s) = 1.07 s, where s is the sale price of the shirt.
We have to find the composite function that can be used to calculate the final price of Sarah's shirt
![c[s(p)]=1.07(s(p))](https://img.qammunity.org/2017/formulas/mathematics/high-school/ycmm16evqsm5f6zgbknh681ttrqerwu5jy.png)
Substitute s(p) = 0.8 p we have;
![c[0.8p]=1.07(0.8p) =0.856p](https://img.qammunity.org/2017/formulas/mathematics/high-school/kevoqrdu89qplq0s9y0v62xmkxm5yse8xm.png)
⇒
, where p is the original price of the shirt
Therefore, the composite function that can be used to calculate the final price of Sarah's shirt by solving for c[s(p)] is, 0.856p