The Changs updated their bedroom by purchasing a new lamp for $89.95 and a comforter set for $239.99. They paid 6 3/5 sales tax on their purchases. If the Changs paid $351.72 total, determine if they paid the correct amount.

First, add the price of the lamp and comforter.
$239.99
+   89.95
=329.94
Then put 6 3/5 into a decimal:
3/5= .6
6.6%
Then change it from a % by dividing by 100.
6.6%= .066
Then multiply 329.94 by 1.066
329.94 x 1.066 = 351.716
                          = 351.72
So, yes. they paid the correct amount