The number of students at a school decreased 20% from 2010 to 2011. If the number of students enrolled in 2011 was k, which of the following expresses the number of students enrolled in 2010
in terms of k?
A) 0.75k
B) 1.20%
C) 1.25K
D) 1.5k

C

Step-by-step explanation:

Okay, here we have a reduction in the number of students by 20% from 2010 to 2011.

In 2011, we had k students, so we want to calculate the number of students we had in 2010.

Let the number of students present in 2010 be x

So mathematically;

x - 20% of x = k

x - 0.2(x) = k

0.8x = k

x = k/0.8

x = k * 1/0.8

x = k * 1.25

x = 1.25k

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

click to let others know, how is it

0.0

0 votes

1

report

read more on -

step-by-step explanation: