Hi,

Looking at just Q. 10 (b)… the first task is to place the first runner (8 ways), the second task is to place the second runner (7 ways), the third task is to place the third runner (6 ways), the fourth task is to place fourth runner (5 ways) and the last task is to place the last runner (4 ways).

Therefore, altogether, there are

(8)(7)(6)(5)(4)=6720 ways of placing the five runners.

Regards,

J.P.

Hi,

I will look at questions five and seven here.

Q.5 The first task is to pick two boys and the second task is to pick two girls. The number of ways of picking two boys from five boys is 5C2=10 and the number of ways of picking two girls from six girls is 6C2=15 so the answer is in fact (10)(15)=150 and not 60.

Q. 7 There are three tasks: pick the first digit, pick the second digit, pick the third digit. If the three digits are allowed to be repeated, there are five ways to do each of these so in total (5)(5)(5)=125 ways to pick a pin.

Regards,

J.P.

I was just looking at the questions on P93 that you recommended. I can’t seem to get my head around the second part of the questions from question 5 to 10. is there any chance you could give me a breakdown of one of them and I might then be able to attempt the rest myself.

Thanks.

]]>