Answer:
The answer is C
Sn=3(1-1/2^n)
Step-by-step explanation:
The probability is 1/5 to get a red ball in 1st draw and a white ball in 2nd draw.
<u>Step-by-step explanation:</u>
- There are 1 red ball and 4 white balls in a box.
- The total number of balls in the box = 1 red + 4 white = 5 balls.
The two balls are drawn without replacement.
<u>Drawing the first ball :</u>
The first draw should be a red ball.
The probability to get a red ball = No.of red balls / Total balls in the box.
We know that, No. of red balls is 1 and total balls in the box is 5.
P(red ball) = 1/5
<u>Drawing the second ball :</u>
The second draw should be a white ball.
The probability to get white ball = No.of white balls / Total balls in the box.
We know that,
No. of white balls is 4.
The total balls in the box after the first draw will be 4 balls.
P(white ball) = 4/4
The probability of getting a red ball on the first drawn and a white ball on the second draw = P(red ball) × P(white ball)
⇒ (1/5) × (4/4)
⇒ 4/20
⇒ 1/5
Therefore, the probability is 1/5 to get a red ball in 1st draw and a white ball in 2nd draw.
If we call the number "x" then:
x*25%=21
x*25/100=21
x=21*4
x=84
Hope this helps. :)
Step-by-step explanation:
x²+2x-3=0
(x²+3x)-(x-3)=0
x(x+3)-1(x+3)=0
(x-1)(x+3)=0
x=1 or x=-3
2(-3n-5)-5(4n-8)
(-6n-10)+(-20n+40)
-26n-30
