Mary will spend $20 + $2 = $<<20+2=22>>22.
Elle and Andrea will spend $1.5 x 4 = $<<1.5*4=6>>6 for the soda.
Elle and Andrea will spend $6 + $10 = $<<6+10=16>>16 for the soda and chicken wings.
Elle, Andrea, and Joe together will spend $16 + $5 = $<<16+5=21>>21.
So, Mary will spend $22 - $21 = $<<22-21=1>>1 more than all of them combined.
#### 1