Answer: 4 Notebooks
Step-by-step explanation:
The number of notebooks is x, the number of markers is 2x+3.
Since the price per notebook is $5 we can write it as 5x, And the price per marker is $2, we can write that as 4x+6
5x+4x+6=42
9x=36
x=4
so he bought 4 notebooks and 11 markers.
CHECK: 4*5=20 and 11*2=22 20+22=42