# Easy Permutation-Combination Solved QuestionAptitude Discussion

 Q. A teacher of $6$ students takes $2$ of his students at a time to a zoo as often as he can, without taking the same pair of children together more than once. How many times does the teacher go to the zoo?
 ✖ A. 10 ✖ B. 12 ✔ C. 15 ✖ D. 20

Solution:
Option(C) is correct

Two students can be selected from $6$ in ${^6C_2} = 15$ ways.

Therefore, the teacher goes to the zoo $15$ times.

## (3) Comment(s)

Pnr
()

I guess it should be like ${^6C_2} \times {^4C_2} \times {^2C_2}$ $= 15 \times 6 \times 2$ $=180$ ways

Am I right?

Ram
()

If there are 6 students and if he can take 2 at a time and not the same pair each time, then the number of times that he as to go to zoo is just 3!!!!

Am i missing something obvious here???

Isha
()

Ram, I guess you are missing the point that it is the not the "same pair"

let's say there are four students

$ABCD$

BUT

ab
ac