Answer:
Correct answer: 342,720 ways
Step-by-step explanation:
If the number of members of the input set is equal to the number of members of the changing string then we use permutations.
First, we will calculate the total number of ways that nine people in the family can be arranged, that number is 9!
Next, we will calculate the number of ways when the twins sit side by side,
that number is 7! · 2! · 2!
When we subtract this number from the total number we will get the required number of ways when the twins do not sit side by side.
9! - 7!· 2! · 2! = 9 · 8 · 7! - 7!· 2! · 2! = 7! ( 72 - 4) = 7! · 68 = 5,040 · 68 =
342,720 ways
God is with you!!!
