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# math

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Seven years ago, Grogg's dad was 8 times as old as Grogg, and 4 years ago, his dad was 5 times as old as Grogg. How old is Grogg's dad currently?

I'm pretty sure im supposed to start by giving variables... but i'm not sure what to do after that

May 29, 2023

#1
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Let g = Grogg's age and d = Grogg's dad's age.

7 years ago, Grogg's dad was 8 times as old as Grogg:

d - 7 = 8(g - 7)

4 years ago, his dad was 5 times as old as Grogg:

d - 4 = 5(g - 4)

Solving for g and d, we get:

g = 11 d = 44

Therefore, Grogg's dad is currently 44 years old.

May 29, 2023
#2
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d - 7 = 8(g - 7)..........................(1)

d - 4 = 5(g - 4)..........................(2), solve for d, g

Use substitution to get:

g ==11 years old

d==39 years old

May 29, 2023
#3
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Let Grogg's age be g and his dad's age be d. We can set up a system of equations to represent the information given in the problem:

Seven years ago, Grogg's dad was 8 times as old as Grogg: d−7=8(g−7)

Four years ago, his dad was 5 times as old as Grogg: d−4=5(g−4)

We can solve this system of equations by substitution. First, we can solve the first equation for g:

g=8d−7​+7

We can then substitute this value of g into the second equation:

d−4=5(8d−7​+4)

We can then solve this equation for d:

d=30

Therefore, Grogg's dad is currently 30 years old.

May 30, 2023
#4
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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.

Guest May 30, 2023
#5
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Grogg's age 7 years ago = x Grogg's dad's age 7 years ago = 8x Grogg's age 4 years ago = x+3 Grogg's dad's age 4 years ago = 5(x+3)

8x+7 = 5(x+3) + 4 3x = 8 x = 8/3

Grogg's dad's age now = 8x+7 = 8(8/3) + 7 = 31