ANSWER
The dot product is 10.
EXPLANATION
The given vectors are (2,4) and (1,2).
If we have the vectors
u=(a,b) and v=(c,d)
Then the dot product of the two vectors is given by

This implies that,

This simplifies to;

50 divided by 4 is 12.5 so there is about 12 or 13 students on each bus.
200, your round 196 up because its at or above 5
2/3+4/9
denominator= 3*9=27
numerator = (18+12)= 30
therefore the answer is 30/27= 10/9