In how many ways can the letters of the word RESULT be arranged so that the vowels appear in even places only?
options:
a) $0$ b) $48$ c) $120$ d) $144$
MyApproach:
RESULT has $2$ vowels and $4$ consonants.
$2$ vowels can be arranged in $3$ places in $3C2$ ways and the rest can be arranged in $4!$ ways.
Therefore $4!$ . $3C2$=$72$
Can Anyone give me the hint if I am wrong?
Best Answer
You took order into account for the consonants but not for the vowels. That's the missing factor $2$.