Answer:

Step-by-step explanation:
To navigate through this problem, start by finding how much each senator can complete in a fixed amount of time. I'll choose 10 as it's the greatest common factor of 30 and 50.
In 10 minutes, the junior senator can complete
of the labyrinth.
In 10 minutes, the senior senator can complete
of the labyrinth.
Therefore, working together, they can complete
of the labyrinth in 10 minutes. Thus, it will take them
to complete one labyrinth.
The amount of time it take them to complete 12 labyrinths is then 
Answer: 8/7
Step-by-step explanation:
To solve 2/7 ÷ 1/4,
Step 1: rewrite as-
2/7 × 4/1
=8/7
I hope this is clear.
Answer:
See the argument below
Step-by-step explanation:
I will give the argument in symbolic form, using rules of inference.
First, let's conclude c.
(1)⇒a by simplification of conjunction
a⇒¬(¬a) by double negation
¬(¬a)∧(2)⇒¬(¬c) by Modus tollens
¬(¬c)⇒c by double negation
Now, the premise (5) is equivalent to ¬d∧¬h which is one of De Morgan's laws. From simplification, we conclude ¬h. We also concluded c before, then by adjunction, we conclude c∧¬h.
An alternative approach to De Morgan's law is the following:
By contradiction proof, assume h is true.
h⇒d∨h by addition
(5)∧(d∨h)⇒¬(d∨h)∧(d∨h), a contradiction. Hence we conclude ¬h.
Slot method
8 optionns n 1st slot
7 options in 2nd slot (since 1 is at 1st slot)
6 options in 3rd slot
5 options in 4th slot
8*7*6*5=1680 ways