You can use the trigonometric identity

.

The requirement that

eliminates -1/6 from being another solution.
Out of 3 coins, if you are given that 1 is on tails, then the most heads you could have is 3 coins - 1 tails = 2 heads.
The probability of getting 3 heads would be 0.
Answer:
28
Step-by-step explanation:
4 / 7 * x = 16
4 * x = 16 * 7
x = 4 * 7
x = 28