Easy and fast way to do it:
Go to google and type, " volume of a cone calculator" and type in the radius and height.
Answer:
the answer to your question is 9,023,000.
I hope this helps you, have a wonderful day!
Number of students = 26
Number of students without siblings = 4
⇒ Number of students with at least one siblings = 26 - 4 = 22
Number of students with brothers = 17
Number of students with sisters = 7
⇒ Number of students with both a brother and a sister = 17 + 7 - 22 = 2
P(student has a brother, given that they have a sister) = 2/7
Answer: 2/7