To maintain the same ratio of 10 pencils to 4 pens, you can set up a proportion:
10 pencils / 4 pens = X pencils / 10 pens
Now, cross-multiply:
10 pencils * 10 pens = 4 pens * X pencils
100 pencils = 4X pencils
Now, solve for X by dividing both sides by 4:
X pencils = 100 pencils / 4
X pencils = 25 pencils
So, in the larger package with 10 pens, there would be 25 pencils.