Answer: B: 20
Step-by-step explanation: We can take 40% as a fraction to make it 4/10, simplifying gives 2/5. 2/5 of 50 is 20!
Hope this Helps!
Answer:
Bobby around 131 minutes and Billy around 111 minutes
Step-by-step explanation:
To solve the problem it is important to raise equations regarding what happens.
They tell us that Billy (Bi) and Bobby (Bo) can mow the lawn in 60 minutes. That is to say that what they prune in a minute is giving as follows:
1 / Bo + 1 / Bi = 1/60 (1)
They say Billy could mow the lawn only in 20 minutes less than it would take Bobby, therefore
1 / Bi = 1 / (Bo-20) (2)
Replacing (2) in (1) we have:
1 / Bo + 1 / (Bo-20) = 1/60
Resolving
(Bo - 20 + B0) / (Bo * (Bo-20) = 1/60
120 * Bo - 1200 = Bo ^ 2 - 20Bo
Rearranging:
Bo ^ 2 - 140Bo -1200 = 0
Now applying the general equation
Bo = 130.82 or Bo = 9.17, <em>this last value cannot be because Billy took 20 minutes less and neither can he prune faster than the two together</em>, therefore Bobby only takes around 131 minutes and Billy around 111 minutes
Checking with equation 1:
1/131 +1/111 = ~ 1/60
Answer:
y=45
x=9
z= 9 root 2
Step-by-step explanation:
This is a right isosceles triangle, so
y=45
x=9
z= 9 root 2
9²+9²=z²
81+81=z²
162=z²
√162=z
z=9√2
The equation of an ellipse is x²/a² + y²/b² =1
a being the distance between the center & x intercept =7
b being the distance between the center & y intercept =5
Hence the equation of this ellipse is:
x²/49 + y²/25 =1
Answer:
Step-by-step explanation:
Given
Solving (a): Point estimate of difference of mean
This is calculated as: 
Solving (b): 90% confidence interval
We have:
Confidence level is: 
Calculate 
The z score is:
The endpoints of the confidence level is:
Split
Hence, the 90% confidence interval is:
Solving (c): 95% confidence interval
We have:
Confidence level is:
Calculate
The z score is:
The endpoints of the confidence level is:
Split
Hence, the 95% confidence interval is:
