If a jellyfish spends 4 hrs and 45 minutes swimming and another jellyfish swims 9 hrs swimming how many hrs do they swim in 6 hrs

In 6 hours, the first jellyfish will have swum 4 3/4 hours.

In 6 hours, the second jellyfish will have swum 6 hours.

Together, they will have swum 4 3/4 + 6 = 10 3/4 hours in 6 hours.

Actually, it depends on how much time they swim and rest in the 6-hour interval you're counting. Here, we have assumed that the interval of observation overlaps completely the times the jellyfish spend swimming, and that the second jellyfish does not rest during that time.

since proposition states that a number is greater than 25, if is true then the number must actually be greater than 25.

this implies that all possible options, except 24, can be accepted