if x is the number of black marbles from a set of 40 colourful marbles, another 30 black marbles are added to it and the probability becomes twice as the first case , what is the value of x

Asked by acshanadhana15 | 6th Aug, 2020, 01:53: PM

Expert Answer:

In the first case, total no. of marbles = 40 and no. of black marbles = x
rightwards double arrow straight P left parenthesis Black space marbles right parenthesis equals straight x over 40
In space the space second space case comma space total space no. space of space marbles space equals space 70 space and space no. space of space black space marbles space equals space straight x plus 30
rightwards double arrow straight P left parenthesis Black space marbles right parenthesis equals fraction numerator straight x plus 30 over denominator 70 end fraction
As space per space the space condition
fraction numerator straight x plus 30 over denominator 70 end fraction equals fraction numerator 2 straight x over denominator 40 end fraction
rightwards double arrow fraction numerator straight x plus 30 over denominator 70 end fraction equals straight x over 20
rightwards double arrow 20 straight x plus 600 equals 70 straight x
rightwards double arrow 50 straight x equals 600
rightwards double arrow straight x equals 12

Answered by Renu Varma | 11th Aug, 2020, 11:50: AM