Hello, mark1950!

An unusual problem . . .

I had to come up with an unusual solution.

When coins are flipped, there are possible outcomes.coins are flipped, and you are given that at least 1 of them is heads.

The probability that at least one other coin is heads is

How many coins do you have?

We are told that at least one of the coins was Heads.

. . Then there are: . outcomes.

We eliminate the case of "no Heads" (all Tails).

We want the probability that at least two coins are Heads.

. . There is 1 outcomes with 0 Heads.

. . There are outcomes with exactly 1 Head.

Hence, there are: . outcomes with at least 2 Heads.

The probability of at least two Heads, given there is at least one Head is

. .

. .

There is no elementary method for solving this equation.

By inspection, I found the solution: .