What type of elasticity is referred to as above and why?

As a result of increase in the price of commodity X from Kshs 35 to Kshs 40, there was an increase in demand for commodity Y from 25 million to 30 million units.

i) What type of elasticity is referred to as above and why?

ii) Calculate the elasticity in i) above.

iii) Interpret your results in ii) above.