You are here:

# Basic Math/How to combine two percentage (which may have overlap)

Edison wrote at 2016-05-28 15:27:57
It's essential that we understand the set equation:

n(A u B) = n(A) + n(B)- n(A n B), wfromhere U=Union and n= intersection of sets, respectively.

We've n(A)=50 and n(B)=60. So, n(A U B)= 110- n( A n B).

Total no of patients with heart disease=100.

Then, n(A n B)<= 100. It follows that -n(A n B)>= -100, or, 110 -n(A n B)>= 10, or, n(A U B)>= 10.

Also n(A U B)<= 100.

Combining them we've,

10>= n(A U B)<= 100. Thus, the total no. of patients having disease A or B or both vary from 10% to100%.

Basic Math

Volunteer

#### Abe Mantell

##### Expertise

Hello, I am a college professor of mathematics and regularly teach all levels from elementary mathematics through differential equations, and would be happy to assist anyone with such questions!

##### Experience

Over 15 years teaching at the college level.

Organizations belong to
NCTM, NYSMATYC, AMATYC, MAA, NYSUT, AFT.

Education/Credentials
B.S. in Mathematics from Rensselaer Polytechnic Institute
M.S. (and A.B.D.) in Applied Mathematics from SUNY @ Stony Brook