I need to use algebra

Seven years ago, Grogg's dad was 6 times as old as Grogg, and 4 years ago, his dad was 4 times as old as Grogg. How old is Grogg's dad currently?

Guest May 7, 2023

#1

#2**0 **

I think 6x4+4 gives you an F in math.

*Seven years ago, Grogg's dad was 6 times as old as Grogg, and 4 years ago, his dad was 4 times as old as Grogg. How old is Grogg's dad currently?*

Call Grogg's age now "G" and his dad's age now "D"

Seven years ago (D – 7) = 6 * (G – 7)

Four years ago (D – 4) = 4 * (G – 4)

Multiply them out D – 7 = 6G – 42 (eq 1)

D – 4 = 4G – 16 (eq 2)

Subtract (eq 2) from (eq 2) – 3 = 2G – 26

23 = 2G

G = 11**.**5

Find D by

plugging G back into (eq 1) D – 7 = (6)(11**.**5) – 42

D – 7 = 69 – 42

D = 27 + 7

**D = 34**

Check answer by

plugging G back into (eq 2) D – 4 = (4)(11**.**5) – 16

D – 4 = 46 – 16

D = 30 + 4

D = 34

_{.}

Guest May 8, 2023