This is a market consisting only of risky securities

In an arbitrage free securities market, there are two non dividend-paying stocks, A and B, both with current price $90. There are two possible outcomes for the prices of A and B one year from now:

Outcome	A	B
1	$100	$80
2	$60	$ X

The current price of a one-year 100-strike European put option on just B is $15.

Determine all possible values of x.