Answer:
$138
Step-by-step explanation:
Let the cost if a tee shirt be $T.
Since the amount of money Raymond have is constant,
8T -8.10= 5T +12.60
8T -5T= 12.60 +8.10
3T= 20.7 (simplify)
T= 20.7 ÷3 (÷3 throughout)
T= 6.90
Thus, cost of one t-shirt is $6.90.
Cost of 20 t-shirts
= 20(6.90)
= $138
