limiting factor

Yo Ltd produces three products: X,Y and Z Product costs are thus X Y Z Direct Material 16 18 24 Labour rate per hour Hours Hours Hours Dept 1 $ 6 3 4 4 Dept 2 $6 6 4 4 Dept $5 5 2 3 Variable overhead per unit $15 $14 $13 Selling price per unit $ 140 $150 $160 Fixed overhead for Quarter 1 $500,000 Current budgeted sales for Quarter 1 (units) X 10,000 Y 5,000 Z 26,000 (a) Prepare a statement showing the expected profit on the budgeted production and sales for Quarter 1 (b) The sales director suggests that sales of each product will rise by 20% in Quarter 2. However, the production director states that labour in Department 1 cannot be increased above the current level. All other production costs will remain unchanged, and labour is freely available in the other two departments. Using the above information, calculate the profit that would result if the most profitable mix of products was produced in Quarter 2 . The ans for part b) show this: Dept.1 Labour Dept 1 Labour hours required hours available - 74000 Produce 1.2x 5000 = 6000 units of Y: 6000x4 =24000 50000 Produce 1.2 x 6000 = 7200 units of Z: 7200 x 4 = 28800 21200 Produce 21200/3 = 7067 units of Product X: 21200 The company should produce 6000 units of Y, 7200 units of Z & 7067 units of X Can i know the ans for part B the labour hour available 74000 where to get it?