A five digit number is to be formed using each of the digits 1, 2, 3, 4 and 5 ONLY ONCE. How many numbers can be formed when 1 and 2 are not together ?	Pick one: A) 48 B) 36 C) 72 D) 60 E) 120
No. of ways the 5 digit number can be formed = 5! = 120   Let us fuse 1 &amp; 2.   No. of ways in which 1 and 2 are together = 4! x 2! (Multiplying by 2! because 1 and 2 can be arranged in 2! ways) = 24*2= 
<gadget id="calculator">24*2</gadget>
<output>48</output>
48   No. of ways 1 &amp; 2 wont be together= 120 - 48= 
<gadget id="calculator">120 - 48</gadget>
<output>72</output>
72   ANSWER:72
<result>C</result>
A five digit number is to be formed using each of the digits 1, 2, 3, 4 and 5 ONLY ONCE. How many numbers can be formed when 1 and 2 are not together ?