How to do these three math problems, please explain them in detail! I copied it myself, and the handwriting is a bit ugly.
5. (1-2/5)/(1/5+1/4) = (3/5)/(9/20) = 4/3 hours, that is, one hour and twenty minutes/is a semicolon, for example, 4/3 is three quarters. Every day, Party A and Party B need 1/20, and two teams need115+1/20. ( 1/ 15+ 1/20) = ...