Question

In a flag post, 1/5 is red, 1/3 is green and the rest is white. If the white part is 7 metres long, find the length of the flag post

Answer 1

Let total length of flag post be x m

We are given,  x = x/5 +x/3 + 7
                       x =        3x+5x/15 + 7
                       x - 8x/15 = 7
           so, 15x-8x/15 = 7 
                  
                     so, 7x/15 = 7
                           x = 15*7/7
                          x= 15m

so length of flag post is 15 m