Answer: There are 3 t-shirts he can buy using his coupon and money altogether.
Step-by-step explanation:
Since we have given that
Amount he can spend at the mall = $27
Amount he get on coupon off at any favourite store =$6
Total money he can spent on T-shirt is given by

Cost of each T-shirt = $11
Number of T-shirt is given by

Hence, there are 3 t-shirts he can buy using his coupon and money altogether.