In a orchestra , 10% the musicians play brass instruments. 15% play woodwin and, %5 play percussion .The other 28 musicians olay stringed insturments. how many musicians are in the orchestra altogther?

Ok so basically 100% is the total amount of like percentage. It stand for 1 . But since you have 3 different percentages, you would use 100% instead.
Firstly, add up the percentages:
10%+15%+28% ( don’t worry about the percentage sign)
= 53% that would be the percentage of the musicians+Woodwind+percussion

28 other play stringed instruments, what you do is u want to change 53%to a normal number , so 53% is out of 100 , so 53/100x100= 53 , and 53+28= 81.

—There are 81 musicians altogether .