You're a little off in your math.
14,697.79 / 1.07 = $13,736.25 Total Sales Cost
14,697.79 - 13,736.25 = $961.54 Sales Tax
Dr Cash 6,000
Dr Accounts Receivable 8,697.79
Cr Sales 13,736.25
Cr Sales Tax Payable 961.54
If this is a perpetual inventory system, you should also have:
Dr Cost of...
Depreciation would be $2,500 ($20,000 / 8) per year.
(a) 31 December 1994;
Truck book value $17,500--Accumulated Depreciation $2,500
(b) 31 December 1995.
Truck book value $15,000--Accumulated Depreciation $5,000