A bag contains 20 balls . These are of three different colours : green red and blue .A ball is chosen at random from the bag . The probability of a green ball is `(1)/(4)`. The probability of a red ball is `(2)/(5)` .
How many balls are red ?

Answer

To solve the problem step by step, we will use the information given about the total number of balls and the probabilities of selecting a ball of each color.

### Step 1: Understand the total number of balls
We know that the total number of balls in the bag is 20.

### Step 2: Set up the probability for red balls
The probability of selecting a red ball is given as \( \frac{2}{5} \).

### Step 3: Calculate the number of red balls
To find the number of red balls, we can use the formula:
\[ \text{Number of red balls} = \text{Total balls} \times \text{Probability of red ball} \]
Substituting the values we have:
\[ \text{Number of red balls} = 20 \times \frac{2}{5} \]

### Step 4: Perform the multiplication
Now we calculate:
\[ 20 \times \frac{2}{5} = \frac{20 \times 2}{5} = \frac{40}{5} = 8 \]

### Conclusion
Thus, the number of red balls in the bag is **8**.