The following figure shows the percentage growth in units of fans and coolers sold in some years. What is the difference between the averages of the growth rate in coolers and fans?

Concept Used: ​

Simple average = $$\frac{\text{Sum of total value}}{\text{Number of value}}$$ 

Average growth in cooler =  $$\frac{231}{4}$$​​
Average growth in fan = $$\frac{95}{4}$$​​

So, 
Difference =  $$\frac{231}{4}-\frac{95}{4} = \frac{136}{4} = 34$$ ​​​