Mathematics Mcqs

Using all the letters of the word “NOKIA”, how many words can be formed, which begin with N and end with A?

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Using all the letters of the word “NOKIA”, how many words can be formed, which begin with N and end with A?

A. 3
B. 6
C. 24
D. 120
Explanation:
There are five letters in the given word.
Consider 5 blanks ….
The first blank and last blank must be filled with N and A all the remaining three blanks can be filled with the remaining 3 letters in 3! ways.
The number of words = 3! = 6.

A boy has nine trousers and 12 shirts. In how many different ways can he select a trouser and a shirt?

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A boy has nine trousers and 12 shirts. In how many different ways can he select a trouser and a shirt?

A. 21
B. 12
C. 9
D. 108

Explanation:
The boy can select one trouser in nine ways.
The boy can select one shirt in 12 ways.
The number of ways in which he can select one trouser and one shirt is 9 * 12 = 108 ways.

In how many different ways can four books A, B, C and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?

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In how many different ways can four books A, B, C and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?

A. 9
B. 12
C. 14
D. 18
Explanation:
The number of arrangement in which A and B are not together
= Total number of arrangements
= Number of arrangements in which A and B are together =4!-3!x2! = 24-12 =12.