Sarah recently got a 10 percent raise. she now purchases 30 percent more in groceries on a weekly basis. sarah's income elasticity for groceries is

Sarah's income elasticity for groceries = percentage increase in grocery / percentage raise in income.

Elasticity for groceries = 30 / 10 = 3

Therefore, Sarah's income elasticity for groceries = 3.

Income elasticity is a value, which measures the responsiveness of the quantity demanded for a good or service to a change in the income of the consumers demanding for the good.