<span>∠ABC ∠BAD is the correct answer
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It takes the son one and half hours to clean the house. To find this you need the equations F+S=2 and F+1=S. (F=father and S=son) You take the F+1 and substitute it in for S in F+S to get F+(F+1)=2. Then you combined like factors, 2F+1=2, and simplify to get F=.5hr. After this you plug .5 in to F+1=S to get (.5)+1=S, meaning it takes the son 1.5 hour to clean the house. 
        
             
        
        
        
The second choice becouse of the total being changed 
        
             
        
        
        
Answer:
First one is 25/2
Step-by-step explanation:
12×2+1=25/2
9×4+1=36/4
cross multiply and you get 
100/
divide both by 2 and you get 50/4 then you divide both by 2 again and you get 25/2 because you can't reduce it anymore