Answer:
I think it's a or b but if I get you this wrong I'm sorry try with a first then b again I aploizge if I get you this wrong.
Answer:

Step-by-step explanation:
The formula of a surface area of a cylinder:

r - radius
H - height
We have r = 40mm and H = 50mm. Substitute:

4 x 5/7 = 20/7
20/7 = 2 6/7
One and seventy-five hundreths is how you say it in word form.
Example:
0.1234
1 is in the tenths place.
2 is in the hundreths place.
3 is in the thousandths place.
Your answer is B. 12.
12 kids are unaccounted for after you subtract the kids that take A1, then A2, the both subjects.