Answer:

Step-by-step explanation:

45 minutes plus 45/2 minutes because of the fact that all the lawns are equal in size and he is mowing 1 1/2 full lawns with a full lawn taking 45 minutes
Answer:
C
Step-by-step explanation:
Base area = (base x height of the base)/2 = (13 x 6)/2 = 39 ft^2
V = base area x height = 39 x 5 = 195 ft^3
Answer:
14
Step-by-step explanation:
4÷2=2 he mows 2 lawns every hour so 7×2-14
Answer:
P(10 ≤ x ≤ 12) = 0.4274
Step-by-step explanation:
Population mean = u = 10
Population Standard Deviation =
= 9
Sample size = n = 43
Sample mean(
) is equal to the population mean. So,
Sample mean =
= 10
Sample standard deviation(
) is equal to population standard deviation divided by square root of sample size. So,
Sample standard deviation =
= 
We have to find the probability that for a random sample of n = 43, the value lies between 10 and 12 i.e. P(10 ≤ x ≤ 12)
P(10 ≤ x ≤ 12) = P(x ≤ 12) - P( x ≤ 10)
We can find P(x ≤ 12 ) and P(x ≤ 10) by converting these values to z scores.
The formula for z score is:

For x =12, we get:

For x =10, we get:

So,
P(x ≤ 12) - P( x ≤ 10) = P(z ≤ 1.457) - P(z ≤ 0)
From the z table,
P(z ≤ 1.457) = 0.9274
P(z ≤ 0) = 0.5
So,
P(x ≤ 12) - P( x ≤ 10) = P(z ≤ 1.458) - P(z ≤ 0) = 0.9274 - 0.5 = 0.4274
So,
P(10 ≤ x ≤ 12) = P(x ≤ 12) - P( x ≤ 10) = 0.4274
Therefore,
The probability that for a random sample of size 43, the mean lies between 10 and 12 is 0.4274.