Question

Seven years ago, Grogg's dad was 6 times as old as Grogg, and 3 years ago, his dad was 4 times as old as Grogg. How old is Grogg's dad currently?

Answer 1

Grogg's dad is 22

Explanation:

Let D = dad's current age

Let g = Grogg's current age

6(d - 7) = g - 7 → 6d - 42 = g - 7 → 6d -35 = g

4(d - 3) = g - 3 → 4d -12 = g - 3 → 4d -9 = g

Set the two equations equal to each other and solve for d

6d - 35 = 4d - 9 Subtract 4d from both sides

2d -35 = -9 Add 35 to both sides

2d = 44 Divide both sides by 2

d = 22

Helping in the name of Jesus.

Answer 2

Explanation:

d = current dad age

g = current grogg age

d-7 = 6(g-7)

d-3 = 4(g-3)

Let's solve the first equation first:

Add 7 to both sides: d - 7 +7 = 6g - 42 + 7 so d = 6g - 35

Substitude d = 6g - 35 for d in d - 3 = 4g - 12

(6g-35)-3 = 4g-12 = 6g-38 = 4g-12

Subtract 4g from both sides: 2g - 38 = -12

Add 38 to both sides: 2g = 26

Easy: g = 13

And now substitude g in for any equations.

d-3 = 52-12

d = 43