To solve this expression, we need to first simplify the fractions within the parentheses.

2 - 1 7/12 = 2 - 1 - 7/12 = 1 - 7/12 = 12/12 - 7/12 = 5/12

3/8 - 1/6 = 9/24 - 4/24 = 5/24

Now we have:

(5/12) ÷ (5/24) × 3 1/4

To simplify the division of fractions, we can multiply by the reciprocal:

(5/12) ÷ (5/24) = (5/12) × (24/5) = 120/60 = 2

Now we have:

2 × 3 1/4

Convert the mixed number to an improper fraction:

3 1/4 = (4 × 3 + 1)/4 = (12 + 1)/4 = 13/4

Now we have:

2 × 13/4

Multiply:

2 × 13/4 = 26/4 = 6 1/2

Therefore, (2-1 7/12):(3/8-1/6)×3 1/4 = 6 1/2.