A bag contains 20 balls (5 green balls and certain number of red balls and blue balls). If 2 balls are taken out one after another without replacement, the probability that the first ball is red and the second ball is green is `2/19`. What is the difference between the number of red and blue balls in the bag?

Options

A. 2
B. None of these
C. 1
D. 4

Answer

To solve the problem step by step, let's break it down:

### Step 1: Understand the problem
We have a bag containing a total of 20 balls, which includes:
- 5 green balls
- Some red balls (let's denote the number of red balls as \( x \))
- Some blue balls (let's denote the number of blue balls as \( y \))

From the information given, we know:
\[ x + y + 5 = 20 \]
This simplifies to:
\[ x + y = 15 \]