Question

the probability of selecting a blue marble at random from a jar that contains only blue, black and green marble is 1/5. The probability of selecting a black marble at random from the same jar is 1/4 . if the jar contains 11 green marble, find the total number of marbles is the jar. ​

Answer 1

Step-by-step explanation:

it will be 20

as five blue

11 green

and 4 black

because probability is given

means 1out of total

so 1 out of 4 black

1 out of 5 blue

Answer = 20

Answer 2

$\sf\bold{\underline{\underline{ANSWER :-}}}$

$\bf\pink{Given :}$

• A jar contains blue, black and green marbles only.
• Probability of selecting a Blue marble is 1/5 i.e, P(B) = 1/5
• Probability of selecting black marble is 1/4 i.e, P(b) = 1/4
• No. of green marbles = 11

$\bf\red{To Find :}$

• Total number of marbles in the jar

$\bf\green{Solution :}$

Let, probability of green marble be P(G)

We know that,

P(E) + P(Not E) = 1

P(G) = 1 – ( (1/5) + (1/4))

= 11/20

Let total number of marbles be x

then,

(11/20) × x = 11

$\boxed{\boxed{x = 20}}$

Therefore, total marbles are 20.