Answer: A
If its around the line and the dots are going the same way than its accurate.
Answer:
100°= angle b(VERTICAL OPPOSITE ANGLE)
100°+x°=180°[co interior angle]
x=180°-100°
x=80°
One fifth is the same as

and 15 is the same as

So just times across,

×

Resulting in(1 x 15= 15, and 5 x 1= 5),

If you need/want to reduce it, divide both numbers by 5. Leaving you with the simplified answer of

or 3. Either answer works. :)
If you have any questions, just comment them down below :)
The answer is 52
x - the number of students in a bus
4 + 9x = 472
9x = 472 - 4
9x = 468
x = 468 / 9
x = 52