Answer: 0.8413
Step-by-step explanation:
Given : Henry has collected data to find that the typing speeds for the students in a typing class has a normal distribution.
Mean : 
Standard deviation : 
Let x be the random variable that represents the typing speeds for the students.
The z-score :-
For x= 51
Using the standard normal distribution table ,the probability that a randomly selected student has a typing speed of less than 51 words per minute :-
Hence, the probability that a randomly selected student has a typing speed of less than 51 words per minute = 0.8413
Answer:
Step-by-step explanation:
Split the trapezoid as pictured below
Find its height and the upper base, then find the area of the trapezoid.
There are 3 pieces, two of them are 45°×45° and 30°×60°×90° triangles
- The ratio of sides of a 30°×60°×90° triangle is 1 : √3 : 2
- The legs of a 45x45 triangle are equal
<u>The above mentioned properties give us:</u>
- h = 16/2 = 8 m
- b = 8√3 ≈ 13.85 m
- a = h = 8 m
<u>Now find the area:</u>
- A = 1/2( 13 + 8 + 13.85 + 13)*8 = 191.4 m²
Correct choice is B
Answer:
Kelly did more math problems.
Step-by-step explanation:
Andrew - 22/13= 1.69
Kelly - 24/12= 2
