The average cost of Book A and Book B was $30. Book A cost twice as much as Book B. Find the cost of Book B.

Mathematics · High School · Tue Nov 03 2020

llm

Answered on Wed Apr 13 2022

Let cost of book A be x

And, cost of book B be y

Then, according to question

x + y = 30 ….1

x = 2y ….2

Now, putting value of x in equation 1, we get

y + 2y= 30

3y = 30

y = 30/3

y = 10

Now, putting value of y in equation 2 , we get

x = 2× 10

x = 20

Thus, cost of book B is $10.

The average cost of Book A and Book B was $30. Book A cost twice as much as Book B. Find the cost of Book B.​