Answer:
0.4
Step-by-step explanation:
Given
60 % wear neither ring nor a necklace
20 % wear a ring
30 % wear necklace
This question can be Solved by using Venn diagram
If one person is choosen randomly among the given student the probability that this student is wearing a ring or necklace is


The sum of probabilty is equal to 1 because it completes the set
Therefore the required probabilty is 0.4
Answer: Option A)
is the correct expansion.
Explanation:
on applying binomial theorem, 
Here a=3c,
and n=6,
Thus, 
⇒ 
⇒
⇒
⇒
Answer:
First look at the number of bricks alone.
Going from 50 bricks to 60 bricks is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 60/50
Next look at the time alone.
Going from 30 minutes to 20 minutes is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 30/20
Now you can just multiply everything.
= 5*60/50*30/20
= 5*6/5*3/2
= 90\10
= 9.
Answer: d
Step-by-step explanation: