Alan

Press the 2nd button and select asin, which is sin^-1

.

$$x^6+y^6=(x^2+y^2)(x^4-x^2y^2+y^4)$$

.

1 nm = 1000 pm so 95 pm = 0.095 nm 

You can do the addition.

.

This assumes the distribution is a normal (Gaussian) one, though the question doesn't say so.  If it were a symmetrical triangular distribution with those parameters, for example, none of the displayed solutions would be right.

I wonder if there's a symmetrical distribution of some sort for which (b) would be the right answer!

.

I used the graphing facilities in MATLAB.  Unfortunately, this is a commercial program, not free open-source.

.

.

Prob of shirt followed by shorts followed by socks = (4/15)*(5/14)*(6/13) = (4*5*6)/(15*14*13)

Prob of shirt followed by socks followed by shorts = (4/15)*(6/14)*(5/13) = (4*5*6)/(15*14*13)

Prob of shorts followed by shirt followed by socks = (5/15)*(4/14)*(6/13) = (4*5*6)/(15*14*13)

... etc.  3! possibilities

So probability = 3!*(4*5*6)/(15*14*13) = 24/91 ≈ 0.264

.

I agree. That's why I cheated on this one and just wrote a simple program to do the calculations!

.