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?
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
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