Can anyone do probability? I will award medal to answer.
In a recent survey, 175 high school seniors were asked about what methods they use to prevent acne including bar soap or face wash.
If a student is randomly selected from the group, what is the probability that they used both bar soap and face wash? Round your answer to the nearest whole percent.
20 students used used bar soap; 10 students used face wash; I don't know how many used both, but 40 students used neither.

Question

Can anyone do probability?  I will award medal to answer.
In a recent survey, 175 high school seniors were asked about what methods they use to prevent acne including bar soap or face wash.
If a student is randomly selected from the group, what is the probability that they used both bar soap and face wash? Round your answer to the nearest whole percent. 
20 students used used bar soap; 10 students used face wash; I don't know how many used both, but 40 students used neither.

anonymous · Answer

So, 105 students used both, I guess.