Answer:
Step-by-step explanation:
9. Correct, D
-3Y + 9X <= 12
3Y - 9X => -12
3Y => -12 + 9X
Y => -4 + 3X
10. D
11. D
12. Correct, B
13. Correct, E
14. A
15. B
Answer:
Fill the gaps in this sequence:
25 36 <u>49</u> 64 81 <u>100</u>
This sequence is the numbers 5, 6, 7, 8, 9, and 10 squared.
Work out the cube root of 343, then square it.
<u>49</u>
Since 7 cubed equals 343, then 7 squared is 49.
When you subtract one square number from another the answer is 7.
What are the two square numbers?
<u>16</u> and <u>9</u>
These are the only squares that fit the criteria.
Write down a number you can square to give an answer bigger than 200 but smaller than 300.
<u>15, 16, 17</u>
All of those answers work. 15² is 225, 16² is 256, and 17² is 289. You can choose any of them to enter in and it should work.
UW and VW are the same so 9
22.5-4.5= 18 then divide the 18 by 2 so 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
Oh wait a minute i have to write this down
