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Dexter, Inc., is a retail store operating in a state with a 6% retail sales tax. The state law provides that the retail sales tax collected during the month must be remitted to the state during the following month. If the amount collected is remitted to the state on or before the twentieth of the following month, the retailer may keep 2% of the sales tax collected. On April 10, 2021 Dexter remitted $216,600 tax to the state tax division for March 2021 retail sales. What was Dexter's March 2021 retail sales subject to sales tax