Astore sells small notebooks for $8 and large notebooks for $10. if a student buys 6 notebooks and spends $54, how many of each size did he buy?

let small notebook = s, large notebook = b

Set the system of equations:

54 = 8s + 10b

s + b = 6

First, solve for b. Isolate the s.

s = 6 - b

Plug in 6 - b for s

54 = 8(6 - b) + 10b

Distribute 8 to all terms within the parenthesis

54 = 48 - 8b + 10b

Simplify

54 = 48 + 2b

Isolate the b. Note the equal sign. What you do to one side, you do to the other. Subtract 48 from both sides

54 (-48) = 48 (-48) + 2b

6 = 2b

Divide

6/2 = 2b/2

b = 6/2

b = 3

Plug in b for 3 in one of the equations.

s + b = 6

s + 3 = 6

Isolate the s. Subtract 3 from both sides

s + 3 (-3) = 6 (-3)

s = 6 - 3

s = 3

small notebook = 3, large notebook = 3

hope this helps