- #1
member 428835
Homework Statement
how many ways can ##a,b,c,d,e,f,g,h,i,j## (first ten letters of the alphabet) be interchanged if ##a,b,c## must be adjacent and if ##d## cannot be touching the ##a## nor can it touch the ##b##?
The Attempt at a Solution
to start, i figure we can take the total number of ways that ##a,b,c## without the ##d## restriction and then subtract the ways the ##d## mingles with the ##a,b##. thus, we have (i think)
$$3!8! - 3 \times 3!7!$$
thanks for the help!