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Seven years ago, Grogg's dad was $9$ times as old as Grogg. Four years ago, Grogg's dad was $6$ times as old as Grogg. How old is Grogg's dad currently?

 Mar 23, 2024

Best Answer 

 #2
avatar+128794 
+1

9(G -7)  = D -7

6(G - 4) = D - 4

 

9G - 63  = D - 7    →   D =  9G - 56

6G -24  = D - 4    →   D =  6G   -20

 

9G   -56  =  6G   - 20

 

3G  =  36

 

G = 12

 

D  = 6(12) - 20  =   52

 

cool cool cool

 Mar 23, 2024
 #1
avatar+16 
+1

 d−4=5(g−4)................(1)

d==5(g - 4) + 4

 

d−7=8(g−7)................(2)

5(g - 4) + 4 - 7==8(g - 7)

5g - 20 + 4 - 7==8g - 56

56 - 20 + 4 - 7==8g - 5g

33 == 3g

g==33/3==11 - sub this into (2) above

 

d - 7==8(11 - 7)

d - 7 ==32

d ==32 + 7 ==39 years - his dad's current age.

 Mar 23, 2024
 #2
avatar+128794 
+1
Best Answer

9(G -7)  = D -7

6(G - 4) = D - 4

 

9G - 63  = D - 7    →   D =  9G - 56

6G -24  = D - 4    →   D =  6G   -20

 

9G   -56  =  6G   - 20

 

3G  =  36

 

G = 12

 

D  = 6(12) - 20  =   52

 

cool cool cool

CPhill Mar 23, 2024

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