To solve the first expression, we follow the order of operations (parentheses first, then multiplication/division, and finally addition/subtraction):

6,25 8 - 3 2/3 : 5,5 + 2,4 4 7/12
= 50 - 3 2/3 : 5,5 + 2,4 4 7/12
= 50 - (11/3) : 5,5 + 2,4 (55/12)
= 50 - 3,666... : 5,5 + 2,4 * 4,583...
= 50 - 3,666... : 5,5 + 11, 0
= 50 - 0,666... + 11
= 49,333... + 11
= 60,333...

Therefore, the result of the first expression is approximately 60,333...

For the second expression:

((1 2/5)² - 1,6) : 0,12
= (7/5)² - 1,6 : 0,12
= (49/25) - 1,6 : 0,12
= 1,96 - 1,6 : 0,12
= 0,36 : 0,12
= 3

So, the result of the second expression is 3.