Total of 10 persons, out of which 6 are women.
So
probability of choosing the first woman = 6/10
probability of choosing the second woman = 5/9
probability of choosing the third woman = 4/8
Since we want all 3 steps to be a success, we need to have success in each of the steps, and the overall probability is given by the multiplication rule:
P(all 3 are women)=6/10*5/9*4/8=120/720=1/6
Gauss' method for addition relies on the fact that you can 'pair' certain numbers together. Look at the example:
1+2+3+4+5+6+7+8+9+10
We could manually add all these together from left to right but a clever way to think about this is if we add together the ends of the sum (10+1) we get 11. If we then move one in from the ends and add these (2+9) we also get 11. This means that 1+2+...+9+10 is the same as 11+11+...+11+11.
Because each 2 numbers adds to 11 we know the total number of 11's we have to add together is the length of the sum divided by 2. In our case 5 (10 ÷ 2). We need to add 5 lots of 11 to get our answer. This is the same as 11 × 5 which is easily seen to be 55.
(If you add the 10 numbers together on a calculator you'll see 1+2+3+4+5+6+7+8+9+10 = 55) so this method really makes it a lot quicker.
Looking at your sequence, if we pair the ends together we get 401 (400+1) and we multiply this by the length of the sequence divided by 2. In your case, 200 (400 ÷ 2).
So the sum of all the numbers from 1 to 400 must be 401 × 200 = 80,200.
Remember the steps:
1. Pair the ends together and add them
2. Times this number by the length of the sequence halved
Hope this helps.
The is answer is definitely D, because he computed the total population of 3,320 in the survey of his targeted people that he specified which was grade school and high school. In order for his computation to work for his market analysis he used the radius of 5m and the 75% he wanted to achieve.
We have that
2.45----------------- > 100%
2.80------------------X
x=2.80*100/2.45=114.29
114.29-100=14.29%-- >14%
the answer is 14%
The answer is C. 5-8 is -3. 5-5 is 0. When you multiply -3 by 0 the outcome is 0!
