Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

(i)[2]

In how many different ways may the 9 letters of the word TELEPHONE be placed in a straight line if P and L are required to be at the ends?

(ii)[1]

How many distinct choices of 4 letters can be made from the 9 letters of the word TELEPHONE if no E is included?

(iii)[2]

How many distinct selections of 4 letters can be made from the 9 letters of the word TELEPHONE if exactly 1 E is included?

(iv)[4]

How many distinct selections of 4 letters can be made from the 9 letters of the word TELEPHONE with no extra conditions?

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Applies $\frac{7!}{3!}\times 2$ or an equivalent method.

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