Answer:
y = 30
Step-by-step explanation:
We can use ratio's to solve this
40 20
----- = -----------
100 20 + y
Using cross products
40 * (20+y) = 20*100
Distribute
800 + 40y = 2000
Subtract 800 from each side
40y = 2000-800
40y = 1200
Divide by 40
y = 1200/40
y =30
Answer:
n + f = 15
Step-by-step explanation:
n + f = 15
n + (6) = 15
n = 15 - 6 (opposite side opposite sign)
n = 9
The answer is 9.5 so the remainder would be 5
Answer:
Percentage of balls which are red = 80%.
Step-by-step explanation:
Let the probability of drawing a red ball be x then the probability of drawing a white ball is 1-x.
There are 5C3 = 10 ways of getting 3 reds in 5 draws so the probability of this is 10* x^3 * (1 - x)^2.
The probability of getting 1 red in 5 draws = 5C1 * x (1-x)^4.
The first probability is 32 times the last.
So we have the equation:
10x^3(1 - x)^2 / 5x(1 - x)^4 = 32
2x^2 / (1 - x)^2 = 32
2x^2 = 32(1 -x)^2
2x^2 = 32( 1 - 2x + x^2)
2x^2 = 32 - 64x + 32x^2
30x^2 - 64x + 32 = 0
15x^2 - 32x + 16 = 0
(5x - 4)(3x - 4) = 0
x = 0.8, 1.333...
The probability must be < 1 so x = 0.8 = 80%.
Answer:38.26 because 2+38=40
40-1.74 =38.26
