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Answers:
x = 7%
y = 2 slips
Explanation:
The expected value is the result of the sum of each value times its probabilities:
Expeted value = probability 1 × value 1 + probability 2 × value 2 + probability 3 × value 3 + .....
Case 1: at the beginning of the contest:
total number of slips: 30 + 15 + 5 = 50
probability 1 = 30/50
value 1 = 5%
probability 2 = (15/50)
value 2 = x%
probability 3 = (5/50)
value 3 = 15%
⇒ Expected value = 6.6% = (30/50) 5% + (15/50)x% + (5/50)15%
⇒ (15/50)x% = 6.6% - (30/50)5% - (5/50)15%
⇒ (15/50) x% = 2.1%
⇒ x% = (50 / 15) 2.1% = 7%
Answer: 7%
2) Case 2: at one point, ...
Yet, the equation for the expected value is:
Expeted value = probability 1 × value 1 + probability 2 × value 2 + probability 3 × value 3 + .....
Only the probabilities have changed, but the discounts are the same. This is x% is the same value found above: 7%.
The total number of slips now is 4 + y + 2 = 6 + y
And the expected value becomes:
8% = [ 4 / (6+y) ] 5% + [ y / (6 + y) ] 7% + [2 / (6 + y)] 15%
From which you obtain:
Mulitplying by 6+ y: 8% [6 + y] = 4×5% + y×7% + 2×15%
⇒ 8% y + 8%×6 = 4×5% + y 7% + 2×15%
⇒ 8% y - 7%y = 4×5% + 2×15% - 6×8%
⇒ 0.01y = 0.2 + 0.3 - 0.48 = 0.02
⇒ y = 2
The answer is 1.75. in fractions it 1/4
Hope this helps! (:
Answer:
120
Step-by-step explanation:
From 20, choose 3:
₂₀C₃ = 120
Here we use combinations instead of permutations because the order doesn't matter.
Answer:
32
Step-by-step explanation:
The facts we have are the height of the small lighthouse is 8, and the base is 2.5. The base of the big lighthouse is 10.
The factor between the base of the big lighthouse and small lighthouse is 4 (10/2.5).
If we apply this to the height, 8x4 = 32
