Amal has a bookcase with n shelves. There are 15 books on each shelf. Using n, write an expression for the total number of books.

15n

Step-by-step explanation:

Amal has a bookcase with n shelves. There are 15 books on each shelf. Using n, write an expression for the total number of books.

The expression for the total number of books is given as:

Number of shelves × Number of books in each shelf

= n × 15 books

= 15n

The answer is in the image 

The answer is in the image 

y=2x+15

where y=Value of coin

x=Age in years

Value of coin after 19 years=2*19+15

=$53

Therefore, Value after 19 years=$53

The answer is in the image 

The answer is in the image 

The solution is given in the image below

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

Salesperson will make 6% of 1800

=(6/100)*1800

=108

Salesperson will make $108 in $1800 sales