Answer:
24. 40 minutes approximately
25. 8 days
Step-by-step explanation:
24. 40 minutes
Anna: 1 hour
Peter: 3 hours
Maria: 6 hours
A way to solve this kind of question is to think about how much they can perform given the same amount of time.
Anna: 1 hour x 6: 6 hours (In 6 hours Anna can clean 6 houses)
Peter: 3 hours x 2 6 hours (In 6 hours Peter can clean 2 houses)
Maria: 6 hours x 1: 6 hours (In 6 hours Peter can clean 1 house)
Working together they can clean the house 9 times faster.
It is 0.66 hours, or approximately 40 minutes
25. 8 days
It climbs 3 feet up but then it falls 2 feet down while sleeping during
the night. So the snail actually climbs 1 foot every day. It happens in the first 7 days. On the 8th day it goes out before sleep.
Gradient, m=(2-0)/(10-0)=1/5
At (10,2), 2=1/5(10)+b
b=0
Equation: y=1/5 x
Hope this can help.
Answer:
0.497
Step-by-step explanation:
Using the binomial probability formula :
P(x =x) = nCx * p^x * (1 - p)^(n - x)
From the question :
n = 6 ; x = 3 ; p = 0.42
P(x = 3) +... P(x = 6)
P(x = 3) = 6C3 * 0.42^3 * (1 - 0.42)^(6-3)
P(x = 3) = 20 * 0.074088 * 0.195112
P(x = 3) = 0.28910915712
Then find p(x = 4).. + p(x = 6)
Using a calculator :
P(X >= x) = 0.497
