Its funny that the question was wrote 2 years ago and everybody comment 2 or 1 years later
Ill be back tomorrow to see if anyone posted anything.
Its right! thank you so much!
you have to agree RSM literally sucks...
INSTEAD OF SAYING ITS WRONG SOMEONE GIVE THE RIGHT ANSWER
To prevent any further " Incorrect" comments on this equation, this answer is correct. Basing of the answer give to us by "Steve" on Feb 19, 2017.
This answer from Steve is actually correct, because 15/(10+15) equals to 0.6, which in fraction form is 3/5. You want this to be out of 100, so you need to multiply the denominator and numerator by 20, which would be 60/100. So, the answer would be 60%.