Answer:
Pr(all will survive in one year) = 0.35 to 2 decimal places
Pr(at least 8 will survive) = 0.39 to 2 decimal places.
Step-by-step explanation:
Probability of a tree surviving one year is 0.9. While not surviving probability is 1 - 0.9 = 0.1
This is obtained from the 90℅ surviving rate for one year planted by the landscaping firm.
Probability that if 10 trees are planted, all will survive for one year is:
0.9x0.9x0.9x0.9x0.9x0.9x0.9x0.9x0.9x0.9 = 0.9^10 = 0.349
Probability that at least 8 will survive in one year can be expressed as
8 survived x 2 not survived +(or) 9 survived x 1 not survived +(or) 10 survived
= [(0.9^8)x(0.1^2) + (0.9^9)x(0.1^1) + (0.9^10)] = 0.391
Since they have the same denominator (4) which is the number on the bottom of the fraction, you can just add the numerators (3 and 4), which are on the top of the fraction, together:
3/4 + 4/4 = 7/4
<span>100-6r=160-10r
Add 10r to both sides
100+4r=160
Subtract 100 from 160
4r=60
Divide 60 by 4
Final Answer: 15</span>
The first answer is 2.5 and I don’t know the last two sorry
