Please help me come up with solutions for A, B & C given the following data to help me study ratios and liquidity. I don't understand how to make the calculations and everytime I do it myself I come up with different answers.

BYP8.2 Shaw Communications Inc. is a diversied Canadian communications company whose core operating business is providing broadband cable television services, Internet, telecommunications services, satellite services, and programming content. The following selected information (in millions) was taken from Shaw's nancial statements for the scal years 2015 to 2017: 2017 2016 2015 Operating revenues (assume all credit) $4,882 $4,884 $4,486 Cash 507 405 398 Accounts receivable (gross) 334 310 494 Allowance for doubtful accounts 48 42 26 Inventories 109 65 60 Other current assets 155 138 78 Total current liabilities 1,392 1,819 1,938 Additional details about Shaw's receivables include the following: Bad debt expense (or provision for doubtful accounts, as Shaw calls it) of $40 (2016, $28; 2015, $29) is included in operating, general, and administrative expenses. Shaw writes off uncollectible accounts receivable against the allowance account based on the age of the account and payment history. Instructions a. Calculate the current ratios, acidtest ratios, receivables turnover ratios, and average collection periods for scal 2017 and 2016. Comment on Shaw's liquidity for each of the years. b. Based on the information provided, calculate the amount of accounts receivable that was written off in 2017. c. Shaw indicates in its notes to the nancial statements that it reduces the risk of uncollectible accounts by billing in advance of providing service. How does billing in advance of providing service reduce the risk of uncollectible accounts