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 #1
avatar+2151 
+1

 

If I give my brother 5 dollars, then we will have the same amount of money. If instead he gives me 25 dollars, then I'll have twice as much money as he will have. How much money does my brother currently have (in dollars)?   

 

Let M stand for My original amount  

Let B stand for Brother's original amount   

 

                                                             (M – 5)  =  (B + 5)   

                                                             (M + 25)  =  (2)(B – 25)  

 

                                                              M – 5  =  B + 5   gives us  M = B + 10    (1)  

 

                                                              M + 25  =  2B – 50                                 (2)  

 

Substitute the value of M from (1)   

into the equation (2)                             B + 10 + 25  =  2B – 50   

 

Combine like terms                                          85  =  B    

 

Brother has 85 dollars ... before they start swapping moneys.   

 

The problem doesn't ask for My original amount but it's B + 10 = 95  

 

Check answer  

 

If I give my brother 5, then I'll have 90 and so will he, so we have the same.  

If my brother gives me 25, then I'll have 120 and my brother will have 60.  

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Jul 18, 2023
 #1
avatar+2151 
+1

 

Will and Grace are canoeing on a lake.  Will rows at 50 meters per minute and Grace rows at 20 meters per minute. Will starts rowing at 2 p.m. from the west end of the lake, and Grace starts rowing from the east end of the lake at 2 p.m. If they always row directly towards each other, and the lake is 3800 meters across from the west side of the lake to the east side, at what time will the two meet?  

 

Will's rate is 50 m/min.  

Grace's rate is 20 m/min.  

 

They're rowing toward each other,  

so their rate of closure is 70 m/min.  

 

The lake is 3800 meters across.  

 

The time it will take them to meet is given by  

                                                                                    Distance  

                                                                            T  =  –––––––  

                                                                                       Rate  

 

                                                                                    3800 m  

                                                                            T  =  –––––––  

                                                                                    70 m/min  

 

The time it takes them to meet                             T  =  54.29 min  

 

Note that (0.29 min • 60 sec/min)  =  17 seconds

 

The time on the clock is                                             2:54:17 pm 

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Jul 18, 2023
 #5
avatar+762 
+1
Jul 18, 2023
 #4
avatar+762 
+1
Jul 18, 2023

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