The surface area of a sphere is

where r is the radius;
The circumference is

so that

using this value we can evaluate the surface area of 1 ball as:

For 100 ball you get:
Haileys work is correct so B should be the right answer
Your answer is- (x being tickets sold and y being the amount of money) y=55x.
This means that for every ticket bought, it costs 55 dollars.
Answer: 
Step-by-step explanation:
Since, The total number of student = 300
Out of which,
The number of students who are only in Maths = 120
And, The number of students who are only in Science = 50
While, the students who are not from any subject = 100
Hence, the number of student who are from both maths and science = Total student - Maths student (only) - science student (only) - None
= 300 - 120 - 50 - 100
= 30
That is, there are 30 students who are both from science and maths,
Thus, the probability of selecting one student who is both from maths and science = 30/300 = 1/10