Question

In a library there are 10 research scholars In how many ways can we select 4 of them?

Answer 1

Out of 10 scholars we can select 4 of them in ${}^{10}{C}_4$ ways ${}^{10}{C}_4=\frac{10\times 9\times 8\times 7}{1\times 2\times 3\times 4}=210$ ways