Answer:
21
Step-by-step explanation:
We know that the sqaure root of 121 = 11.
So, A - 10 = 11
=> A = 21
Answer:
7/10 or 0.7
Step-by-step explanation:
cross multiply to get 40x+20=48
subtract 20 from both sides to get 40x=28
divide both sides by 40 to get 7/10
HOPE THIS HELPS!!!:)
Answer:
The proportion of students whose height are lower than Darnell's height is 71.57%
Step-by-step explanation:
The complete question is:
A set of middle school student heights are normally distributed with a mean of 150 centimeters and a standard deviation of 20 centimeters. Darnel is a middle school student with a height of 161.4cm.
What proportion of proportion of students height are lower than Darnell's height.
Answer:
We first calculate the z-score corresponding to Darnell's height using:

We substitute x=161.4 ,
, and
to get:

From the normal distribution table, we read 0.5 under 7.
The corresponding area is 0.7157
Therefore the proportion of students whose height are lower than Darnell's height is 71.57%