Somebody can estimate the length of a book by using a ruler and rounding it to the nearest whole number.
What divided by 8 and are there answer choices
1 = 1 x 1
1 factors
2 = 1 x 2
2 factors
3 = 1 x 3
2 factors
4 = 1 x 4
4 = 2 x 2
3 factors
5 = 1 x 5
2 factors
6 = 1 x 6
6 = 2 x 3
4 factors
7 = 1 x 7
2 factors
8 = 1 x 8
8 = 2 x 4
4 factors
9 = 1 x 9
9 = 3 x 3
3 factors
10 = 1 x 10
10 = 2 x 5
4 factors
11 = 1 x 11
2 factors
12 = 1 x 12
12 = 2 x 6
12 = 3 x 4
6 factors
13 = 1 x 13
2 factors
14 = 1 x 14
14 = 2 x 7
4 factors
15 = 1 x 15
15 = 3 x 5
4 factors
16 = 1 x 16
16 = 2 x 8
16 = 4 x 4
5 factors
17 = 1 x 17
2 factors
18 = 1 x 18
18 = 2 x 9
18 = 3 x 6
6 factors
19 = 1 x 19
2 factors
20 = 1x 20
20 = 2 x10
20 = 4 x 5
6 factors
So they are 6, 8, 10, 14 and 15 on the number line
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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1) This is a combination, so use ⁴⁰C₂.
⁴⁰C₂ = 780
There are 780 handshakes in total.
2) I got my solution by using the combinations formula. Or another way you could do this is to add up... 39 + 38 + 37 + 36 + 35 + 34 + 33 + 32 + 31... +1. You will end up with 780 (I did this to double check my work).
3) The quickest way to figure this out if Drake invited 1,000 people is to use the natural numbers formula = n(n+ 1)/2.
Plug the numbers in: 999(1000)/2 = 499,500
If Drake invited 1,000 people, there would be 499,500 handshakes.
You turn the percentage to a decimal which is 75%=0.75
