What effect does the availability of many substitute have on the elasticity of demand for a good

If the price of suntan lotion increases from $6 to $8 per bottle and quantity demanded decrease from 900,000 bottles to 845,000 bottles, what is the price elasticity of demand for suntan lotion?

Economists in Champaign have been studying the local market for Truly. They've found that the demand for Truly can be described by the following equation: P= 40 - 0.15Q. What is the price elasticity of demand(using the Midpoint method)  when moving from a quantity of 100 to 130? ( input your answer in absolute value, and round it to include 2 decimal places.)

Why  might  one  expect  the  elasticity  of  supply  of  a commodity  to be greater in the long run than in the short run?

Assuming the price of an imported decaffeinated coffee of £4 increases to £7 and the sudden increase does not affect the quantity demanded, the price elasticity of demand here would be said to be?