Science (English Medium) Class 11 - CBSE Question Bank Solutions

Let A = {a, b, {c, d}, e}. Which of the following statement are false and why? 

\[a \subset A\]

Let A = {a, b, {c, d}, e}. Which of the following statement are false and why?

\[\left\{ a, b, e \right\} \subset A\] 

How many different numbers of six digits each can be formed from the digits 4, 5, 6, 7, 8, 9 when repetition of digits is not allowed?

How many different numbers of six digits can be formed from the digits 3, 1, 7, 0, 9, 5 when repetition of digits is not allowed?

How many four digit different numbers, greater than 5000 can be formed with the digits 1, 2, 5, 9, 0 when repetition of digits is not allowed?

Serial numbers for an item produced in a factory are to be made using two letters followed by four digits (0 to 9). If the letters are to be taken from six letters of English alphabet without repetition and the digits are also not repeated in a serial number, how many serial numbers are possible?

A number lock on a suitcase has 3 wheels each labelled with ten digits 0 to 9. If opening of the lock is a particular sequence of three digits with no repeats, how many such sequences will be possible? Also, find the number of unsuccessful attempts to open the lock.

Let \[A = \left\{ \phi, \left\{ \phi \right\}, 1, \left\{ 1, \phi \right\}, 2 \right\}\] Which of the following are true? \[\left\{ 1 \right\} \in A\]

Let \[A = \left\{ \phi, \left\{ \phi \right\}, 1, \left\{ 1, \phi \right\}, 2 \right\}\]Which of the following are true?\[\left\{ 2 \left\{ 1 \right\} \right\} \not\subset A\] 

Write down all possible subsets of each of the following set:

\[\left\{ \phi \right\}\]

Evaluate the following:

¹⁴C₃

Evaluate the following:

¹²C₁₀

Evaluate the following:

³⁵C₃₅

Evaluate the following:

^n + 1C_n

Evaluate the following: