Joey's sock drawer is unorganized and contains 3 black dress socks, 5 black ankle socks, 7 brown dress socks, and 6 brown ankle socks. what is the probability that joey will blindly reach into his sock drawer and pull out a sock that is brown or a dress sock?

i got 1/3 by doing: 13/21+10/21-16/21=7/21 which is 1/3 simplified. is this correct?

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label?