If Isabella has $15 more than Giselle, she has $120+$15 = $135
Combined, Isabella and Giselle has $135+$120=$<<135+120=255>>255
Isabella has $45 more than Sam, meaning Sam has $135-$45=$90
Together, Sam, Isabella, and Giselle has $255+$90=$<<255+90=345>>345
if they donate the money to three shoppers at their local town's supermarket who share it equally, each shopper will receive $345/3=$<<345/3=115>>115
#### 115