Step 1: Calculate the probability of studying for at least 2 hours:
\[P(X \geq 2) = P(X = 2) + P(X = 3) + P(X = 4).\]
Step 2: Insert values from the probability distribution:
\[P(X \geq 2) = k(2) + k(5 - 3) + k(5 - 4).\]
Step 3: Substitute \( k = 0.15 \):
\[P(X \geq 2) = 0.15(2) + 0.15(2) + 0.15(1).\]
Step 4: Perform the calculation:
\[P(X \geq 2) = 0.3 + 0.3 + 0.15 = 0.75.\]
The probability of the student studying for at least 2 hours is 0.75.