please give a solution of this

4. Consider the following problems. Each problem is unrelated to the other. [1+2+2=5] a) Selling price per unit, Tk. 29; total fixed expenses, Tk. 30,400; variable expenses per unit, Tk. 13. Find total sales in units to achieve a profit of Tk. 8,000, assuming no change in selling price. b) Sales, Tk. 51,000; variable expenses, Tk. 18,000; fixed expenses, Tk. 18,000; net income, Tk. 15,000. Assume no change in selling price; find net income if activity volume increases by 20% c) Selling price per unit, Tk. 48; total fixed expenses, Tk. 106,000; variable expenses per unit, Tk. 36. Assume that variable expenses are reduced by 25% per unit, and the total fixed expenses are increased by 15%. Find the sales in units to achieve a profit of Tk. 23,000, assuming no change in selling price