A book costs $4 more than a CD. The CD is 30% cheaper than a $20 album. How much does the book cost?
Step-by-step reasoning process below:
18
The CD is 30 / 100 * 20 = $6 cheaper than the album.

So the cost of the CD is 20 - 6 = $14.

The book is $4 more expensive than the CD, which means it cost 14 + 4 = $18.

.

The final answer: 18