Determine the missing amounts in each of these four separate situations a through d. a b $ 400 $ 1,260 Supplies available-prior year-end Supplies purchased during the current year Total supplies available Supplies availablecurrent year-end Supplies expense for current year 3,000 1,200 $ 6,500 7,700 2,800 3,200 (650) (1,350) 8,400 (700) 4,588 1,200