Multiply 3(2x - 1)(x + 2)
1 answer:
You might be interested in
Answer:
20.33%
Step-by-step explanation:
We have that the mean (m) is equal to 87.5, the standard deviation (sd) 6.25 and the sample size (n) = 12
They ask us for P (x <86)
For this, the first thing is to calculate z, which is given by the following equation:
z = (x - m) / (sd / (n ^ 1/2))
We have all these values, replacing we have:
z = (86 - 87.5) / (6.25 / (12 ^ 1/2))
z = -0.83
With the normal distribution table (attached), we have that at that value, the probability is:
P (z <-0.83) = 0.2033
The probability is 20.33%
Answer:
The total number of pupils and their teachers = 530
Step-by-step explanation:
No. of girls in the school = 280
The ratio boys to girls is 3:4 and that of teachers to girls is 1:7
∴ The ratio boys to girls is 3x : 4x where, 4x = 280
and The ratio of teachers to girls is x : 7x where, 7x = 280
4x = 280
= x
70 = x
So, the no. of girls in the school = 4x = 4(70) = 280 and the no. of boys in the school = 3x = 3(70) = 210
7x = 280
= x
40 = x
So, the no. of girls in the school = 7x = 7(40) = 280 and the no. of teachers in the school = x = 40
∴ The total number of pupils and their teachers = 280 + 210 + 40
= 530