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Question number???Plz someone write the fully working for this and explain me!
It is October November 10 Paper 11!
Can anyone help me out with the b part of this Q. I have my exams tomorrow and I cant figure this out View attachment 22026
the answer for this question is :they already said leave the answer in surds..so when u do the equation x= -b ±√(b^2-4ac) / 2a u will end up with x =1/4 (-20 + √40) or 1/4(-20-√40) u can simplify it..did u get it now ?
thx u veryyyyyyy muchh.
its a lotQuestion number???
Sum of coded values = -60The amounts of money, x dollars, that 24 people had in their pockets are summarised by Σ(x − 36) = −60 and Σ(x − 36)2 = 227.76. Find Σx and Σx^2\
Does anybody have a guide on how to solve questions like these? They are really confusing :/
Can any1 help with a(ii) ? thanks in advance
5ai) For three courses a dish has to be picked from each course.
For the first course there are 3 options so 3C1
For the second course there are 5 options so 5C1. But each dish has two possible choices of being served with either fries or potatoes. So the actual combination is 2* 5C1
For the third course 3C1
Total no of ways = 3C1 * 5C1* 2 *3C1 = 90
ii) Only two courses can be picked. Possible choices - Starter-main, Starter-dessert, Main-dessert
Starter-main= 3C1* 5C1 *2 = 30
Starter-dessert= 3C1*3C1 = 9
Main-dessert= 5C1* 3C1 *2 =30
Total = 30 + 30 +9 =69
b) You have to find the different ways to divide not different arrangements. So, 14C5* 9C5 * 4C4 =252252.
The answer will be the same no matter which table you decide to chose first.
I understood the Σx part, but not the Σx^2 part :/ Why did you do that?Sum of coded values = -60
Σx = -60 + (24*36) = 804
Σ(x-36)^2 = 227.76
Expand LHS:
Σ(x^2 - 72x + 1296) = 227.76
Σx^2 - 72Σx + Σ1296 = 227.76
We have Σx = 804 and Σ1296 = (1296)(24) = 31104
Σx^2 - (804)(72) + 31104 = 227.76
Σx^2 = 27011.76
I expanded Σ(x-36)^2 it to pull out the term Σx^2. That is what we are supposed to find.I understood the Σx part, but not the Σx^2 part :/ Why did you do that?
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