Question

mr.singh's bookstore sells special red pens which ae available only on boxes of 5 pens or 9 pens or 13 pens.if you want 14 pens you can buy the exact number by buying a box of 5 pens ad a box of pens,but you'd not be able to buy 4 pin or 11 pens exactly by any combination of the sets.what would be the largest number of pens that you would not be able to buy in exact number answer

Answer 1

it is infinite



or the answer will be 584

Answer 2

The answer can be infinite.

Since we have the boxes of 5 pens, 9 pens and 13 pens.

You can add on any combination such as 5 + 9 + 13 = 23 that means that you won’t be able to buy 24 pens in total.

Hence, we can keep on increasing the set and will come up with so many combinations that are not possible.