If the sum of a number and seven is doubled, the result is four less than the number. Find the number.
2 answers:
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Answer:
a) 0.0256 = 2.56% probability of 4 heads.
0.1296 = 12.96% probability of 4 tails.
b) The probability is 0.0576 = 5.76%.
c) 6 outcomes given 2 heads in 4 tosses. 0.3456 = 34.56% probability of 2 heads in 4 tosses
Step-by-step explanation:
For each throw, we have these following probabilities:
0.4 = 40% probability of heads.
0.6 = 60% probability of tails.
(a) Compare the probability of 4 heads in 4 tosses and 4 tails in 4 tosses.
4 heads:
4 throws, each with 0.4 probability of heads. So
0.0256 = 2.56% probability of 4 heads.
4 tails:
4 throws, each with 0.6 probability of tails. So
0.1296 = 12.96% probability of 4 tails.
(b) Determine the probability of H T H T in 4 tosses.
H = 0.4, T = 0.6. So
The probability is 0.0576 = 5.76%.
(c) Determine the number of outcomes that give us 2 heads in 4 tosses in any order. What is the probability of 2 heads in 4 tosses (use (b) and the number of outcomes)
Number of outcomes:
The possible outcomes are:
H - H - T - T
H - T - H - T
H - T - T - H
T - H - H - T
T - H - T - H
T - T - H - H
6 outcomes given 2 heads in 4 tosses.
Each with probability 0.0576, as found in b)
6*0.0576 = 0.3456
0.3456 = 34.56% probability of 2 heads in 4 tosses