Answer: 35
Step-by-step explanation:
Given : A bag contains four red marbles, two green ones, one lavender one, three yellows, and one orange marble.
Total = 4+2+1+3+1=11
To find sets of four marbles include none of the red ones, we need to exclude red marbles when we count the total number of marbles.
Then, the total marbles(exclude red) =11-4=7
Now, the combination of 7 marbles taking 4 at a time is given by :-
Hence, the number of sets of four marbles include none of the red ones = 35
Answer:
1. always
2. sometimes
Step-by-step explanation:
Two lines are coplanar if they lie in the same plane or in parallel planes. There is ALWAYS a plane which contains two parallel lines (see first attached image for details).
Two lines that lie in parallel planes are sometimes parallel. For example, see at second image. Planes and
are parallel. Consider pair of lines
and
- they are parallel, but if you consider the pair of lines
and
, you can see they are not parallel.
