Question

The kindergarten teacher has $25$ kids in her class. She takes $5$ of them at a time, to zoological garden
as often as she can, without taking the same $5$ kids more than once; Then the number of visits, the
teacher makes to the garden exceeds that of a kid by:

• A. ${}^{25}{C}_5{-}^{24}{C}_4$
• B. ${}^{24}{C}_7$
• C. ${}^{25}{C}_5{-}^{24}{C}_5$
• D. ${}^{24}{C}_4$

Answer 1

Answer: (A)

${}^{25}{C}_5{-}^{24}{C}_4$

Number of times teacher visit garden $={}^{25}{C}_5$

$\because$ Same $5$ kids are not taken again let's remove $1$ kids at a time.

Then no. of visits kid make $={}^{25-1}{C}_{5-1}={}^{24}{C}_4$

So, a no is ${}^{25}{C}_5-{}^{24}{C}_4.$

Hence, the answer is ${}^{25}{C}_5-{}^{24}{C}_4.$