On a certain bus- route, the charge for each adult is 20k and for each child 10k. On a Friday morning the conductor collected a total of 66 naira as fares. If 120 of the passengers were children, how many of the passengers were adults?

Answer 1

Let the number of adult passengers be x.
The total fare collected from adults is 20k * x = 20000kx.
The total fare collected from children is 10k * 120 = 1200k.
The total fare collected is 20000kx + 1200k = (20000x + 1200) k.
The total fare collected is 66000 k.
Thus, 66000k = (20000x + 1200)k.
By equating the coefficients of k, we get:
66000 = 20000x + 1200.
Subtracting 1200 from both sides, we get:
66000 - 1200 = 20000x.
So, 64800 = 20000x.
Dividing both sides by 20000, we get:
x = 64800 / 20000
x = 3.24.
Since we are counting passengers, the number of adults can only be a whole number. Hence, there were 3 adult passengers. Answer: \boxed{3}.