There are 11 software engineers and 7 civil engineers in a company. Theyare selecting member for row. In how many ways can they be seated in a row so that no two of the civil engineers will sit together?  Choose the correct option
A) 10!×11!/5! B) 9!×11!/4! C) 11!×12!/5! ways D) 9!×5!/4! E) 5!×6!/7!
11 software engineers can be arranged in 11! ways. ...(A)   Now we need to arrange civil engineers such that no two civil engineers can be seated together. i.e., we can arrange 7 civil engineers in any of the 12 (=11+1) positions marked as * below.   * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 *   (where 1, 2… 11 represent software engineers)   This can be done in 12P7 ways. ... (B)   From (A) and (B),   required number of ways   = 11! × 12P7   =11!×12!/5!   11!×12!/5! ways
<result>C</result>
There are 11 software engineers and 7 civil engineers in a company. Theyare selecting member for row. In how many ways can they be seated in a row so that no two of the civil engineers will sit together?