can you please help me solve this!

Problems 19-21 are based on the following information A&Y Inc. considers a 7-year project that requires $500,000 of investment in new machinery and $40,000 in NWC (that will stay constant for the entire life of the project). At the end of the project the equipment will be sold for a salvage value of $70,000. The cost of capital is 10%, the equipment belongs to a CCA class with d=40%, and the corporate tax rate is 30% Problem 19: Prof. Gandhi has pointed out that A&Y does not need $40,000 NWC for the entire length of the project. In fact, it needs only $25,000 of NWC during the first 3 years of the project and $40,000 during the remaining 4 years. If A&Y follows Prof. Gandhi's advice, i.e., invest only $25,000 in NWC at t=0 and add an additional $15,000 to NWC only at the beginning of year 4 (so that it will be available from t4 forward), by how much the NPV of the project be increased? Problem 20: Prof Reynolds was able to use his industry connections to get a 3% discount on the equipment (i.e., it can be purchased for $485,000 instead of $500,000). By how much will this increase the project's NPV? Problem 21: Prof Kerr has developed new equipment care procedures that are able to increase the salvage value of the equipment by $20,000 (so it becomes $90,000 instead of $70,000). By how much will this increase the project's NPV