30 bài tập trắc nghiệm hoán vị chỉnh hợp tổ hợp mứ...

A \(C_{10}^2\)

B \(\left\{ {1;\,\,2} \right\}\)

C \(2!\)

D \(A_{10}^2\)

A \({20^2}\)

B \({2^{20}}\)

C \(C_{20}^2\)

D \(A_{20}^2\)

A \(C_n^2 = \frac{{n\left( {n - 1} \right)}}{2}.\)

B \(C_n^2 = n\left( {n - 1} \right).\)    

C \(C_n^2 = 2n.\)          

D \(C_n^2 = \frac{{n!\left( {n - 1} \right)!}}{2}.\)

A \(30240.\)

B \(25.\)

C \(50.\)

D \(252.\)

A \(A_{2020}^2\)    

B \({2^{2020}}\)

C \(C_{2020}^2\)

D \({2020^2}\)

A \({2^9}\)

B \(C_9^2\)

C \({9^2}\)

D \(A_9^2\)

A \(C_n^k = \dfrac{{n!}}{{k!}}\)

B \(C_n^k = kC_n^{k - 1}\)

C \(C_n^k = \dfrac{{n!}}{{\left( {n - k} \right)!}}\)

D \(C_n^k = C_n^{n - k}\)

A \(1140\)

B \(2920\)

C \(1900\)

D \(900\)

A \(C_7^1\).

B \(C_7^7\).        

C \({P_7}\).        

D \(A_7^1\).

A 4 cách.

B 64 cách.

C 6 cách.

D 24 cách.

A \(A_{15}^4.\)

B \({4^{15}}.\)

C \({15^4}.\)

D \(C_{15}^4.\)

A \(10\).

B \(45\).

C \(90\).

D \(24\).

A \(14\)

B \(48\)

C \(6\)

D \(8\)

A \(24\)

B \(6\)

C \(12\)

D \(225\)

A \(120\)

B \(168\)

C \(288\)

D \(364\)

A \({5^{10}}\)

B \(A_{10}^5\)

C \(C_{10}^5\)

D \({P_5}\)

A \(A_{30}^4\)

B \({30^5}\)

C \({5^30}\)

D \(C_{30}^5\)

A \(100\).

B \(255\).

C \(150\).

D \(81\).

A \({30^5}\).

B \(A_{30}^4\).

C \(C_{30}^5\).

D \({30^6}\).

A \(A_{18}^3\)

B \(C_{18}^3\)

C \(6\)

D \(\dfrac{{18!}}{3}\)

A \(A_{18}^2\)

B \(C_{18}^2\)

C \(9\)

D \(\dfrac{{18!}}{2}\)

A \({P_n} = \left( {n - 1} \right)!.\)

B \({P_n} = \left( {n + 1} \right)!.\)

C \({P_n} = \dfrac{{n!}}{{n - 1}}.\)

D \({P_n} = n!.\)

A 5

B 12

C 24

D 96

A \(C_n^2 = \dfrac{{n\left( {n - 1} \right)}}{2}\)

B \(C_n^2 = n\left( {n - 1} \right)\)

C \(C_n^2 = 2n\)

D \(C_n^2 = \dfrac{{n!\left( {n - 1} \right)!}}{2}\)

A \(A_7^3\).

B \({7^3}\).

C \({3^7}\).

D \(C_7^3\).

A \(A_{12}^4.\)

B \(C_5^4 + C_7^4.\)

C \(4!\).

D \(C_{12}^4.\)

A \(4005\)

B \(5004\)

C \(5040\)

D \(4050\)

A 120. 

B 360. 

C 150. 

D 720.

A \(5!\)

B \(4!\)

C \(3!\)

D \(2!\)

A \(\dfrac{{2019!}}{{2!.2017!}}.\)

B \(\dfrac{{2019!}}{{2!}}.\)

C \(\dfrac{{2017!}}{{2019!}}.\)

D \(\dfrac{{2019!}}{{2017!}}.\)