Let the present age of A be $A$ years and the present age of B be $B$ years.
From the first statement, "A is 6 years older than B":
$ A = B + 6 \quad \quad (1) $
From the second statement, "10 years ago":
The condition is "B's age was three quarters of A's age":
$ B - 10 = \frac{3}{4}(A - 10) \quad \quad (2) $
Substitute $B$ from equation (1) into equation (2). From (1), we get $B = A - 6$.
Substitute $B = A - 6$ into equation (2):
$ (A - 6) - 10 = \frac{3}{4}(A - 10) $
Simplify the equation:
$ A - 16 = \frac{3}{4}(A - 10) $
Multiply both sides by 4 to eliminate the fraction:
$ 4(A - 16) = 3(A - 10) $
Expand both sides:
$ 4A - 64 = 3A - 30 $
Rearrange the terms to solve for $A$:
$ 4A - 3A = 64 - 30 $
$ A = 34 $
The present age of A is 34 years.