Remember that when you find 30% of the number you have to subtract the 30% from your original $90 because it is 30% off the original price.
We know, cos A + cos B = 2cos(C+D)/2 × cos(C - D)/2
So,
cos 130 + cos 110 + cos 10
cos 130 + 2cos (110+10)/2 × cos( 110-10)/2
cos 130 + 2cos 60 × cos 50
cos ( 180 - 50 ) + 2cos60 cos 50
We know, cos ( 180 - A ) = -cos A
2cos 60 cos 50 - cos 50
Also, cos 60 = 0.5
2×0.5 cos 50 - cos50
cos 50 - cos 50
0 = RHS.
Hence proved
Answer:

Step-by-step explanation:
The two angles given in the diagram are alternate interior angles. Alternate interior angles are congruent. Therefore:
(4x)° = (x + 60)°
Use the equation to solve for the value of x

Subtract x from both sides


Divide both sides by 3


Answer:
(a) 20 ways
(b) 0.05 or 5%
Step-by-step explanation:
(a) Assuming that the order in which people are chosen does not matter, the number of ways to select 3 people out of possible 6 is given by the following combination.

(b) In a random sampling procedure, every outcome is just as likely to occur. Therefore, the chances that any particular sample will be the one selected are:
