since 10 students is the most amount of kids on each bus, you can fit less than 10 people on it. so i don't know if the question wants each bus to have to same amount of students or each bus having different amounts.
2x + 8y = 5
2/ 24x - 4y = -15
2x + 8y = 5
48x - 8x = -30
+
--------------------------
50x = -25
x = -1/2
2 * -1/2 + 8y = 5
-1 + 8y = 5
8y = 6
y = 6/8
y = 3/4
x = -1/2 y = 3/4
First of all, it is 2r

and it would be divide by 3.14 (pi) and then you should have the diameter. Then divide by 2 to find radius.
Answer:
Company B
Step-by-step explanation:
A is $0.15/min
because 76/500
B is $0.12/min
because 54/450
Company B is cheaper so it would be the better deal