Answer:

Explanation:
Here, the total number of television = 40,
Let x be the number of P television,
So, the number of Q television = (40 - x)
Now, the price of each P television is $ p,
∴ The total price of P televisions = xp dollars,
Also, the price of each Q television is $ q,
∴ The total price of Q televisions = (40-x)q dollars,
Thus, the total price of 40 television = xp + (40-x)q = x(p-q) + 40q,
Hence, the average price =


According to the question,




Therefore, there were
P model televisions.