Word | know | Unknown
Language| 12 | x
Total | 180 | 28980
Use cross multiply:
12(28980) = 180(x)
347760 = 180x
347760/180=1932
Answer:

And the best option would be:

Step-by-step explanation:
We assume that the distribution for the random variable is:

For this case we want to calculate the following probability:

And we can use the normal standard distribution or excel and we got:

And the best option would be:

A ruler as that is the only option that can measure segments
2 is a,c,d
3, none of the options are correct.
4 could be 3v + 5m
5 can be 11(2x+y)
For the first digit of the required 20-digit number, we can have 9 choices for the number, those are the digits 1 to 9. In the second digit of the number, we will only have 8 choices. That is because, we don't want to write a number in the second digit that is similar to the first digit and the third digit.
Similarly, in the third digit's place, we will only have 8 choices because we do not want the digit to be similar to the second digit and the fourth digit. This will go on up until the 19th digit. In the 20th digit, we will also have 9 choices (from 0-9) but we do not want the digit to be similar to the 19th digit.
From the explanation given above, we have the number of ways,
n = 9 x 8^(19 - 1) x 9 = 1.459 x 10^18
<em>ANSWER: 1.459 x 10^18</em>