Question

A shelf contains 8 different travel books, of which 5 are about Europe and 3 are about Africa.
a) i Find the number of different ways the books can be arranged if there are no restrictions. ii Find the number of different ways the books can be arranged if the 5 books about Europe are kept together,
b) 3 DVDs and 2 videotapes are to be selected from a collection of 7 DVDs and 5 videotapes. Calculate the number of different selections that could be made.
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Answer 1

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Since books C and D are arranged first and second starting from the right of the shelf, therefore, only books A, B and E will change order.

Thus, an arrangement problem involves 3 items and the number of different order is given by 3!.

Hence, the number of different orders in which books A, B and E may be arranged is 3.!

$\bf\pink{\textsf{Answered By MrAkdu}}$