Answer: b) 84
Step-by-step explanation:
Let p be the prior estimate of the required proportion.
As per given , we have
p =0.5 (The probability of getting heads on a fair coin is 0.5)
Significance level : 
Critical z-value (using z-value table ) : 
Confidence interval width : w= 0.18
Thus , the margin of error : 
Formula to find the sample size ( if prior estimate of proportion is known.):-

Substitute the values , we get

Simplify ,
[Round of to the next whole number.]
Hence, the number of times we would have to flip the coin =<u>84</u>
hence, the correct answer is b) 84
1/5(2x - 10) + 4x = -3(1/5x + 4)
0.4x - 2 + 4x = -0.6x - 12
4.4x - 2 = -0.6x - 12
5x - 2 = -12
5x = -10
x = -2
Answer:
Step-by-step explanation:
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