Answer:
a) 20.16; b) 20.49 and 21.51
Step-by-step explanation:
We use z scores for each of these. The formula for a z score is
.
For part a, we want the 20th percentile; this means we want 20% of the data to be lower than this. We find the value in the cells of the z table that are the closest to 0.20 as we can get; this is 0.2005, which corresponds with a z score of -0.84.
Using this, 21 as the mean and 1 as the standard deviation,
-0.84 = (X-21)/1
-0.84 = X-21
Add 21 to each side:
-0.84+21 = X-21+21
20.16 = X
For part b, we want the middle 39%. This means we want 39/2 = 19.5% above the mean and 19.5% below the mean; this means we want
50-19.5 = 30.5% = 0.305 and
50+19.5 = 69.5% = 0.695.
Looking these values up in the cells of the z table, we find those exact values; 0.305 corresponds with z = -0.51 and 0.695 corresponds with z = 0.51:
-0.51 = (X-21)/1
-0.51 = X-21
Add 21 to each side:
-0.51+21 = X-21+21
20.49 = X
0.51 = (X-21)/1
0.51 = X-21
Add 21 to each side:
0.51+21 = X-21+21
21.51 = X
Answer:
We have x^3^2 which is x^3*2 = x*6 times x*4 which is x*10
Hope this helped and brainliest please
Answer:
Step-by-step explanation:
(f*g)(x) = (-5x² + 2x + 7) (x +1)
= x* (-5x² + 2x + 7) + 1*(-5x² + 2x + 7)
= x*(-5x²) + x*2x + x*7 - 5x² + 2x + 7
= -5x³ + 2x² + 7x - 5x² + 2x + 7
= - 5x³ + <u>2x² -5x²</u> <u>+ 7x + 2x </u>+7 {Combine like terms}
= -5x³ - 3x² + 9x + 7
4) (f*g)(x) = (x² + 2x + 4)(x - 2)
= x*(x² + 2x + 4) - 2*(x² + 2x + 4)
= x*x² + x*2x + x*4 - 2*x² - 2*2x -2* 4
= x³ + 2x² + 4x -2x² -4x - 8
= x³ - 8
D, because tutoring and receptionist is UPTO 20 hours and the money is AT LEAST 200