There are only green pens and red pens in a box.
There are three more red pens than green pens in the box.
Sheila is going to take at random two pens from the box.
17
The probability that Sheila will take two pens of the same colour as
35
Work out the two different numbers of green pens that could be in the box.
Your final line must be written in the form, There could be ... or ... green pens.
In your working, let g stand for the number of green pens.