Let's solve the expression step by step:
1. First, convert the mixed numbers to improper fractions:
$$1\frac{17}{15} = \frac{1 \cdot 15 + 17}{15} = \frac{15 + 17}{15} = \frac{32}{15}$$
$$1\frac{1}{12} = \frac{1 \cdot 12 + 1}{12} = \frac{12 + 1}{12} = \frac{13}{12}$$
$$2\frac{20}{33} = \frac{2 \cdot 33 + 20}{33} = \frac{66 + 20}{33} = \frac{86}{33}$$
2. Now, subtract the first two fractions:
$$\frac{32}{15} - \frac{13}{12}$$
To subtract these fractions, we need a common denominator. The least common multiple (LCM) of 15 and 12 is 60.
$$\frac{32}{15} = \frac{32 \cdot 4}{15 \cdot 4} = \frac{128}{60}$$
$$\frac{13}{12} = \frac{13 \cdot 5}{12 \cdot 5} = \frac{65}{60}$$
$$\frac{128}{60} - \frac{65}{60} = \frac{128 - 65}{60} = \frac{63}{60}$$
Simplify the fraction: $$\frac{63}{60} = \frac{21}{20}$$
3. Multiply the result by the third fraction:
$$\frac{21}{20} \cdot \frac{86}{33}$$
$$\frac{21 \cdot 86}{20 \cdot 33} = \frac{1806}{660}$$
4. Simplify the fraction:
$$\frac{1806}{660} = \frac{903}{330} = \frac{301}{110}$$
5. Convert the improper fraction to a mixed number:
$$\frac{301}{110} = 2\frac{81}{110}$$
So, the final answer is:
$$\left(1\frac{17}{15} - 1\frac{1}{12}\right) \cdot 2\frac{20}{33} = 2\frac{81}{110}$$
Answer: $$2\frac{81}{110}$$