The probability of being a girl in this class is 4/7 and there are 12 boys. Find the total number of students.

Mathematics

1 answer:

vladimir1956 [14]2 years ago

3 0

Answer: 28 students

Step-by-step explanation:

The probability of being a girl is 4/7 which means that the probability of being a boy is 3/7 as the fractions must add up to 1.

Assuming the number of people in class is x then the following expression can be used to solve for it;

$\frac{3}{7} x = 12\\\\3x = 12 * 7\\\\x = \frac{12 * 7 }{3} \\\\x = 28$

You might be interested in

Answer the question with explanation;

PSYCHO15rus [73]

Answer:

The statement in the question is wrong. The series actually diverges.

Step-by-step explanation:

We compute

$\lim_{n\to\infty}\frac{n^2}{(n+1)^2}=\lim_{n\to\infty}\left(\frac{n^2}{n^2+2n+1}\cdot\frac{1/n^2}{1/n^2}\right)=\lim_{n\to\infty}\frac1{1+2/n+1/n^2}=\frac1{1+0+0}=1\ne0$

Therefore, by the series divergence test, the series $\sum_{n=1}^\infty\frac{n^2}{(n+1)^2}$ diverges.

EDIT: To VectorFundament120, if $(x_n)_{n\in\mathbb N}$ is a sequence, both $\lim x_n$ and $\lim_{n\to\infty}x_n$ are common notation for its limit. The former is not wrong but I have switched to the latter if that helps.