Let x represent the number of pens, and y represent the number of pencils.
We know that x + y = 24 (as it states in the question that altogether, there's 24 pens and pencils). We also know that x = y + 6 (as it also states that there were 6 more pens than pencils, which is number of pencils + 6).
So, given this information, we can rewrite our original expression of x + y = 24 by replacing the x with our second expression of x = y + 6:
x + y = 24
(y + 6) + y = 24
Now you just need to combine all the like terms and rearrange the expression to isolate the y value and find out the number of pencils:
(y + 6) + y = 24
2y + 6 = 24
2y = 18
y = 9
Now that you know that y (the number of pencils) = 9, you know that the number of pens will be 6 more than that, which is 9 + 6 = 15 (because the question says that there are 6 more pens than pencils).
Therefore, you have 15 pens and 9 pencils.
