Total possibilities would be:
(1,1)(1,2)(1,3)(1,4)(1,5)(1,6)
(2,1)(2,2)(2,3)(2,4)(2,5)(2,6)
(3,1)(3,2)(3,3)(3,4)(3,5)(3,6)
(4,1)(4,2)(4,3)(4,4)(4,5)(4,6)
(5,1)(5,2)(5,3)(5,4)(5,5)(5,6)
(6,1)(6,2)(6,3)(6,4)(6,5)(6,6)
You want 5 on at-least one, so mark 5th column & 5th raw.
There are 6 in both lines with 1 common = (5,5)
In short, Your Answer would be 11
Hope this helps!
Answer:
Step-by-step explanation:
Let a , b , c & d be the no. of chairs in hall A , B , C & D respectively.
Given,
b = 4a
c = a + 15
d = a + 8 + 4a = 5a + 8
Now,
Total no. of chairs (T) = a + b + c + d
= a + 4a + a + 15 + 5a + 8
= 11a + 23
Now,
Average chairs in each hall (Avg) = T/4
= (11a + 23)/4
