Let x be the portion of consumers that purchased another type of tea. To find x, you can follow the steps:
Step 1) Organize the data
Tea Pencentual of consumers
Green 5/15
Jasmine 2/15
Helbal 5/15
Other x 
Sum 1 
Step 2) Knowing that the sum of the percentual has to be equal to 1 (100%), organize the expression. 

Step 3) Get the least common multiple.

Step 4) Isolate x. 

Answer: 3/15 of consumers purchased another type of tea.