Answer:
a) 
b) 
Step-by-step explanation:
From the question we are told that:
3 coin are tossed
Therefore
Sample space 
Generally the sets that correspond with the result of at most one tail is therefore given as follows

Therefore
The result is at most one tail when

Answer:

Step-by-step explanation:

You have to prime factorise 81 and then you will get <u>9</u> as the answer.
Answer:
143
Step-by-step explanation:
Your equation to find x is:
140+146/2 = 143
Answer:
Area of parallelogram is equal to 
Step-by-step explanation:
It is given length pf parallelogram which is equal to base of parallelogram is b=15 cm
Height of parallelogram h = 7.5 cm
We have to find the area of the parallelogram.
Area of parallelogram is equal to multiplication of base and height.
Therefore area of parallelogram is,
, here b is base and h is height.
So 
Therefore area of parallelogram is equal to 