If Emily has 20 credits, and Aria has 2 times as many, then Aria has 2*20=<<20*2=40>>40 high school credits.
Emily has twice the number of high school credits Spencer has, meaning Spencer has 20/2=<<20/2=10>>10 high school credits.
Altogether, the three have 40 + 20 + 10=<<40+20+10=70>>70 high school credits.
Twice the total number of high school credits the three have is 2*70=<<2*70=140>>140
#### 140