See the attached picture:
Answer:
I'm not sure if there is enough information here. If you are asking how many books or bookmarks she can buy, you'll need a total amount of money :).
Answer:

Step-by-step explanation:
<u><em> Step(i):-</em></u>
Given that the function
f(x) = 
Now integrating on both sides, we get

= 
<u><em>Step(ii):-</em></u>
Let 


= 
=
= 
= 

= 
= 
= 
= 
<u><em>Final answer:-</em></u>
= 