Question

How to solve these questions?

Answer 1

A) to calculate the royalties earned for the
first you need to multiply 6.7 by .1 to find how much the author made per book in royalties for the first 1500 books since she made 10% of the sales price per book (this should give you.67 dollars per book).  now you need to multiply 1500 by .67 to find out how much she made in royalties for the first 1500 books (this should give you 1005 dollars).

Then you have to multiply 6.7 by .12 to find how much the author made per book in royalties for the next 2000 books (you should get .804 dollars per book).  Now you need to multiply 0.804 by 2000 to find how mush was made from the next 2000 books in royalties (you should get 1608 dollars).

Then you have to multiply 6.7 by .15 to find how much the author made in royalties for the rest of the books sold (you should get 1.005 dollars per book).  Then you need to subtract 3500 (1500+2000) from 4789 to find the amount of books remaining (which is 1289 books).  To find the amount of rayalties collected for the remaining amount, you need to multiply 1289 by 1.005 (which is 1295.4 dollars). 
To get the total amount of royalties collected you need to add up the three amounts from above (1295.4+1608+1005=3908.4).  Therefore the author collected 3908.4 dollars in royalties.

b) First you need to find the amount made off of the books.  To do this you need to multiply 4789 by 6.7 to get 32086.3.  Then subtract the total money made from the books (32086.3) by the publishing cost plus the amount they had to pay in royalties (25408.4) to get the profit the publishers made from the books (6677.9 dollars).  Since we now know that the profit the publishers made, you just divide the profit of the publisher by the total money made from the book sales (6677.9/32086.3=0.2081) and than multiply that value by 100% to get 20.81%.
 Therefore we know that the publishers had a percent profit of 20.81%. 

c) Use the equation A=P(1+(r/n))^nt
A= total amount
r=rate (4.8% or 0.048 in this case)
n=number of times per year the interest is compounded (12 in this case)
t=number of years (4 years in this case)
P= the starting amount (in this case 21500)
When you pug everything in you should get an amount of 26040.94 dollars.  To find the interest the publisher had to pay you subtract the total amount (26040.94) by 21500 to get 4540.94 dollars.
Therefore the publisher had to pay 4540.94 dollars in interest.

d) First you need to multiply 17.50 by 0.08 to find the amount the author makes per book (RH 1.4 per book).  Then you have to multiply the amount the author makes per book (1.4) by the amount of books sold (2408) to find the amount the author makes on total sales (you should get RH 3371.2).  
Therefore the author made RH 3371.2 in royalties.

I hope this helps.  Let me know in the comments if anything is unclear.