Question 1 (19 marks): Sarah has a monthly income of $1,800 to spend on goods X and Y, where good Y is the composite good (therefore priced at $1 per \"unit"). Good X is a type of food. The price of X is initially $5 per unit, then this price increases to $7 per unit. Sarah's MRS, measured at any point along her indifference curve, is given by the formula: Y/3X. In 911; diaggam [for parts Ital-ltd\