Answer:
28 were senior citizens
A common denominator between 9 and 5 is 45.
4 ·5 20 2 ·9 18
9 ·5 45 5 ·9 45
20/45 + 18/45 is 38/45
38/45=x/180
solve for x
38 ·4= 152
45 ·4= 180
152 out of the 180 visitors were NOT senior citizens.
180-152=28
28 visitors were senior citizens
Hope this helped :)
