Draw 4 budget lines for food and shelter as directed.
The consumer has $500 income, faces an absolute price for shelter of 10, and a budget line slope of -5. (Shelter is on the horizontal axis.)
Given (a) above as a starting point, the price of each good doubles.
Given (a) above as a starting point, the absolute price of food stays the same, but its relative price doubles.
Given (a) above as a starting point, the absolute price of food is cut in half.