A. 18 - 25 because 29% plus 23% equals 52%
Answer:
1. 6
2. 2
Step-by-step explanation:
1. 9-t=3(t-5)
9-t=3t-15
+t +t
9=4t-15
+15 +15
<u>24</u>=<u>4t</u>
4 4
6=t
2.5(5y+1)=10y-25
25y+5=10y-25
+25 +25
25y+30=10y
-25 -25
<u>30</u>=<u>-15y</u>
15 15
2=y
Answer:
% Decrease = 11.45%
Step-by-step explanation:
Original Population = 5893
Expected Population = 5218
% Decrease = Original Population - Expected Population / Original population
% Decrease = (5893 - 5218 ) / 5893
% Decrease = 675/5893
% Decrease = 0.11454268
% Decrease = 11.454268%
% Decrease = 11.45% approximately.
Answer:
p = 40/9
Step-by-step explanation:
p - 10p = -40
-9p = -40
p = -40/(-9
p = 40/9
Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
