Question 9,10 & 11 please. Thank you

QUESTION 9 Which of the following statements regarding inventory systems is false? A perpetual system keeps track of detailed purchases and sales. Cost of goods sold is calculated at the end of the period only in a perpetual system. A periodic Inventory system is less costly than a perpetual inventory system Accounting records are continually updated in a perpetual inventory system QUESTION 10 On August 26, 20Y7. a piece of machinery was sold for $65.000 cash. The machine was originally purchased in 2074 for $95.000. To date, it had accumulated depreciation of $15,000. Which of the following is true on the date of disposition? The building had a net book value of $65.000 A loss on sale of $15.000 should be recorded. A gain on sale of $30.000 should be recorded The building had a fair market value of $80.000 QUESTION 11 Net sales revenue is calculated by Sales Revenue. Sales Discounts Sales Revenue Sales Returns Sales Revenue - Sales Discounts. Sales Returns Sales Revenue - Sales Discounts - Sales Returns