Answer:
"Donna loaned $30 to her brother. He then paid her back $30 the next day" is the correct situation
 
        
             
        
        
        
Answer:
40 problems in 100 minutes
Step-by-step explanation:
This is a ratio problem. 
You first divide 30 minutes by three to get how many problems she can do in 10 minutes. What you do to one side you do to the other side. So then, you should have 4 problems in 10 minute. Then, you multiply 10 by 10 and 4 by 10 to get 40 problems in 100 minutes.
 
        
             
        
        
        
Answer:
-3
Step-by-step explanation:
-7x=-2x+15
collect like terms
-7x+2x=15
-5x=15
divide both sides by -5
x=15/-5
x=-3
 
        
                    
             
        
        
        
Answer:
It should be 5 but my brain is literally dead
Step-by-step explanation:
Please give brainlest
 
        
             
        
        
        
Answer:
Erin gets £90
Step-by-step explanation:
Ratio = 5 : 2 : 7
Money with Erin = 5x
Money with Faye = 2x
Money with Sachin = 7x 
Faye gets £90 less than Sachin
7x -  2x = 90
       5x = 90
         x = 90/5
         x = 18
Money with Erin = 5*18 = 90