A coin is flipped 20 times. The results are 12 heads and 8 tails. Determine the theoretical probability of getting heads.

The theoretical probability of getting heads is; 12%

We are given;

Number of times coin is flipped = 20 times

Number of heads gotten = 12 heads

Number of tails gotten = 8

Assuming the coin is fair, then;

p = 0.5 and q = 0.5

Using binomial probability formula we have;

P(getting heads) = ²⁰C₁₂ * 0.5¹² * 0.5⁽²⁰ ⁻ ¹²⁾

P(getting heads) = 125970 * 0.00000095367431640625

P(getting heads) = 0.12 or 12%

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x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18