Name: Amrita

Who is asking: Parent
Level: Secondary

I need help to do this question

On a popular television game show, contestant must first answer a question by placing 4 given events in ascending or desending order in the quickest time.

(a) if a contestant does not know how any of the events should be arranged, how many different ways could the question be answered?

Answer: 4!= 24

(b)a contestant has to arrange the events that correspond to A, B, C, and D. one contestant is positive that event D follows directly after avent B, but does not know about the other s. how many different ways could this contestant arrange the letters A, B, C, and D, list the possibility

Answer: which I didn't get

Hi Amrita,

If the contestant is going to put event D directly after event B then event D cannot be first. Thus the contestant can put A, B or C first. If B is first then D must be second and that leaves A and C. Thus the only possible arrangements with B first are

BDAC and

If the contestant puts A first then either B or C can be second. If B is second then D is third and the order is

ABDC If C is second then B must be third and the order is ACBD

What are the possibilities if C is first?


Amrita, after I sent my answer Denis sent another solution. He wrote:

Tie a string around BD so they look like one letter - now you have just 3 'letters' to deal with A, BD and C

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