Question

A. bag contains 40 balls some of them are red
Summer yellow and the rest are black
the probablity of drawing
a red ball and yellow ball are
1/4 and 2/5 respectively
black​

Answer 1

Answer:

Let no. of red balls = x, no. of blue balls =y and no.of black balls = z.

Probability of drawing a red ball = P (red ball) =  

20 /11  =  40 x

​⇒ x=22

Probability of drawing a blue ball = P (Blue ball) =  

5 /1  =  40 y

​⇒ y=8

∴ No of black balls = 40- 22 -8 =10

Answer 2

let the number of red ball bi x

so,

$\frac{1}{4} \times 40 = 10 \: balls \: are \: red$

$let \: the \: no \: of \: yellow \: ball \: be \: y \\ so. \\ \frac{2}{5} \times 40 = 16 \\ 16 \: balls \: are \: yellow \\ no. \: of \: black \: ball \: is \\ = 40 - (10 + 16) =$

$40 - (10 + 16) \\ = 40 - 26 = 14 \: balls \\ 14 \: balls \: are \: black$