Answer:
a) Calculate the probability that at least one of them suffers from arachnophobia.
x = number of students suffering from arachnophobia
= P(x ≥ 1)
= 1 - P(x = 0)
= 1 - [0.05⁰ x (1 - 0.05)¹¹⁻⁰
]
= 1 - (0.95)¹¹
= 0.4311999 = 0.4312
b) Calculate the probability that exactly 2 of them suffer from arachnophobia? 0.08666
= P(x = 2)
= (¹¹₂) x (0.05)² x (0.95)⁹
where ¹¹₂ = 11! / (2!9!) = (11 x 10) / (2 x 1) = 55
= 55 x 0.0025 x 0.630249409 = 0.086659293 = 0.0867
c) Calculate the probability that at most 1 of them suffers from arachnophobia?
P(x ≤ 1)
= P(x = 0) + P(x = 1)
= [(¹¹₀) x 0.05⁰ x 0.95¹¹] + [(¹¹₁) x 0.05¹ x 0.95¹⁰]
= (1 x 1 x 0.5688) + (11 x 0.05 x 0.598736939) = 0.5688 + 0.3293 = 0.8981
To solve this, we are going to use the compound interest formula:

where

is the final amount after

years

is the initial investment

is the interest rate in decimal form

is the number of times the interest is compounded per year
For the first 4 years we know that:

,

,

, and since the problem is not specifying how often the interest is communed, we are going to assume it is compounded annually; therefore,

. Lest replace those values in our formula:




Now, for the next 6 years the intial investment will be the final amount from our previous step, so

. We also know that:

,

, and

. Lets replace those values in our formula one more time:




We can conclude that Collin will have <span>£3691.41 in his account after 10 years.</span>
Answer:
129.32
Step-by-step explanation:
You multiply 6.8 by both values in the parenthesis and then subtract that number and lastly, take that value and add it to 33.1 which equals 129.32