Lets write equation of a function:
y = kx + n
Direct variation in simple is equation of a line which has n=0 or in other words which y to x ratio is k.
First option gets 7=7 but it isnt direct variation because n is not equal to 0
third option is indeed correct. once we implement coordinates (2,7) we get 7=7
Answer is 
y = 7/2x
        
             
        
        
        
Step-by-step explanation:
a. (0.60x + 0.70y)- 50 = 10
 <=> 0.60x + 0.70y = 60
b. (x+y) = 5(x-y)
 x+y=5x-5y
 <=> 4x - 6y = 0
 
        
             
        
        
        
Answer:
1/60 probabiliity
Step-by-step explanation:
You have two independent events that you want to put together.
Let Pr. mean "probability"
Pr(5 from 10 cards and 2 on a dice ) = Pr(5 from 10 cards) * Pr( 2 on a dice)
Pr(5 from 10 cards and 2 on a dice ) =(1/10) * (1/6)
= 1/60
Pr(5 from 10 cards and 2 on a dice ) =0.0167
or 1.67% probability
 
        
             
        
        
        
Answer:
B: 192pi - 144
Step-by-step explanation:
Area of the sector = (120/360) * pi * r^2
Area of the sector = 1/3 * pi * 24 * 24
Area of the sector = 192 * pi
Now to find the area of the triangle.
The triangle is an isosceles triangle That means two of its sides are equal. They are equal to the radius of the circle, which is 24.
the small angles are equal to 
2x + 120 = 180    Subtract 120 from both sides
2x = 60               Divide by 2
x = 60/2
x = 30
The height of the triangle is derived from sin(30) = opposite / hypotenuse
sin(30) = 1/2
hypotenuse = 24
1/2 = opposite / hypotenuse
1/2 = opposite / 24                      Multiply both sides by 24
1/2 * 24 = opposite
opposite = 12
The height = 12
r = 24
Area of the triangle = 1/2 * 12 * 24
Area of the triangle = 144
So the area of the shaded area = 192*pi - 144 which looks like B