Question

after working together for T hours on a common task, two workers have completed fractional parts of the job equal to T/4 and T/6. What fractional part of the task has been completed?

Answer 1

Adding the two fractions, we get:
$\frac{T}{4}+\frac{T}{6}=\frac{3T+2T}{12}=\frac{5}{12}T$
Therefore (5/12)T of the job has been completed.