Bobby has an aquarium with twice as many fish as Sarah's has.  Sarah has 5 more fish in her aquarium than Tony does.  Tony has 3 times as many fish in his aquarium as Billy does.  Billy has 10 fish.  How many fish do all 4 people have put together?
Since Tony has 3 times as many fish as Billy's 10, that means Tony has 3*10= <<3*10=30>>30 fish
Sarah has 5 more fish than Tony's 30, meaning she has 5+30= <<5+30=35>>35 fish
Bobby has twice as many fish as Sarah does, meaning he has 35*2=<<35*2=70>>70 fish
Therefore, altogether there are 10+30+35+70=<<10+30+35+70=145>>145 fish
#### 145