Demand for water bottle is inelastic.

Because water bottle doesn't have any close substitute. It is a necessary goods as water is use in day to life or activities. Therefore it's demamd is inelastic when we compare to luxary.

Lets take an Example

If price of water bottle increases from 10 to 15 per bottle. Its demamd decrease from 100 to 90

Ed = -%? in Quantity demanded/ %?in price

%? in quantity demanded = (90-100/100)*100

= -10%

%?in price = (15-10/10)*100

= 50%

Put values in Elasticity formula

Ed =-(-10%/50%)

= 1/5

=0.2

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