To solve this problem, we can use algebra to set up two equations with two unknowns. Let's say Abby's current age is "A" and her dad's current age is "D".
From the first piece of information, we know that 7 years ago, Abby's dad was 6 times as old as Abby. This can be written as:
D-7 = 6(A-7)
Simplifying this equation, we get:
D-7 = 6A - 42
D = 6A - 35
From the second piece of information, we know that 3 years ago, Abby's dad was 4 times as old as Abby. This can be written as:
D-3 = 4(A-3)
Simplifying this equation, we get:
D-3 = 4A - 12
D = 4A - 9
Now we can equate the expressions for D from the two equations, since they both represent Abby's dad's current age:
6A - 35 = 4A - 9
Solving for A, we get:
2A = 26
A = 13
So Abby is currently 13 years old. We can plug this value back into either equation for D to find Abby's dad's current age:
D = 6A - 35 = 6(13) - 35 = 43
Therefore, Abby's dad is currently 43 years old.