I do not agree with the solution because it does not give any real solution. It only gives possible solution. If you plug the value 4 in the original equation you will get 8 and the square root of 8 is a complex number. Thus 4 is an extraneous solution....
There is a total of 24 outcomes 4 letters • 6 numbers = 24 possible outcomes There are 6 different outcomes when it comes to each letter. (a1, a2, b1, b2 etc) so getting a5 is a 1/24 chance because there 24 outcomes and only one of them is a5
