Nicole and Nancy read a total of 18 books this summer. Nancy read 3 more than Nicole. How many did Nicole read?

Assuming Nicole = x, Nancy = y

[tex]x + y = 18 \\ y = x + 3[/tex]

Substitute that into
[tex]x + x + 3 = 18 \\ 2x = 15 \\ x = 7.5[/tex]

Answer : Nicole read 7.5 books.

Hope this helps. - M