It is econometrics, please provide clear solutions

The role of the credit department includes: a. evaluating customers' credit applications to determine whether they meet the company's approval standards. b. approving all credit applications in order to avoid losing sales. c. collecting cash from customers. d. following unwritten approval standards for processing customers' credit applications.

Alpha company uses the periodic inventory system for purchase & sales of merchandise. discount terms for both purchases & sales are, 2/10, n30 and the gross method is used. unless otherwise noted, fob destination will apply to all purchases & sales. the value of inventory is based on periodic system. on january 1, 2016, beginning inventory consisted of 350 units of widgets costing $10 each. alpha prepares monthly income statements. the following events occurred during the month of jan.: dateactivitya.jan. 3purchased on account 350 widgets for $11 each.b.jan. 5sold on account 400 widgets for $30 each. paid freight out with petty cash of $150.c.jan. 10purchased on account 625 widgets for $12 each.d.jan. 11shipping cost for the january 10 purchased merchandise was $400 was paid with a cheque by alpha directly to the freight company.e.jan. 12returned 50 widgets received from jan. 10 purchase as they were not the correct item ordered.f.jan. 13paid for the purchases made on jan. 3.g.jan. 21sold on account 550 widgets for $30 each. paid freight out with petty cash of $250.h.jan. 22authorize credit without return of goods for 50 widgets sold on jan. 21 when customer advised that they were received in defective condition.i.jan. 25received payment for the sale made on jan. 5.j.jan. 26paid for the purchases made on jan. 10.k.jan. 31received payment for the sale made on jan. 21.use this information to prepare the general journal entries (without explanation) for the january events. if no entry is required then enter the date and write "no entry required."

What is the cause of smoky exhaust?