A man has 440 coins and notes consisting of 50 Kobo notes and 10 Kobo pieces. If the total value of the money is N60, how many 50 Kobo notes does he have?

Let $x$ be the number of 50 Kobo notes.
Let $y$ be the number of 10 Kobo pieces.
The total number of notes and pieces is 440:

$$x + y = 440 \quad (1)$$

The total value is N60. Since 1 Naira (N) = 100 Kobo, N60 is equal to $60 \times 100 = 6000$ Kobo.
The total value equation is:

$$50x + 10y = 6000 \quad (2)$$

From equation (1), we can express $y$ in terms of $x$:

$$y = 440 - x$$

Substitute $y = 440 - x$ into $50x + 10y = 6000$:

$$50x + 10(440 - x) = 6000$$ $$50x + 4400 - 10x = 6000$$

Combine the terms with $x$:

$$40x + 4400 = 6000$$

Subtract 4400 from both sides:

$$40x = 6000 - 4400$$ $$40x = 1600$$

Divide by 40:

$$x = \frac{1600}{40}$$ $$x = 40$$

The number of 50 Kobo notes is 40.

The final answer is $\text{40}$.