Find the probability that one ball is white when two balls are drawn at random from a basket that contains 9 red, 7 white and 4 black balls.

Distance covered = 550 meter. = 0.55 km
Speed of the train = 55 km/hr

So time taken = 0.55 / 55 =1/100 hr = (60 x 60 )/100 sec = 36 sec

? = 95^3.7 ÷ 95^0.9989 = 95^?
? 95^{(3.7 - 0.9989)} = 95^?
? 95^2.7011 = 95^?
? ? = 2.7011 ? 2.7

Therefore x = 21%

Total no.of boys : no. of girls = 13:27

       27             :                13

Let the price of the mixed variety be Rs. x per kg. By the rule of alligation, we have :

Cost of 1 kg of type 1 rice           Cost of 1 kg of type 2 rice  

?(20-x)/(x-15) = 2/3 

? 60 - 3x = 2x - 30

  ? x = 18.

pool : kerosene 

   3  :  2(initially) 

   2  :  3(after replacement)

  R e m a i n i n g Q u a n t i t y I n i t i a l Q u a n t i t y = 1 - R e p l a c e d Q u a n t i t y T o t a l Q u a n t i t y

(for petrol)    2 3 = 1 - 10 k

 => K = 30

 Therefore the total quantity of the mixture in the container is 30 liters.

Let the capacity of the pot be 'P' litres.
Quantity of milk in the mixture before adding milk = 4/9 (P - 8)
After adding milk, quantity of milk in the mixture = 6/11 P.
6P/11 - 8 = 4/9(P - 8)
10P = 792 - 352 => P = 44.

The capacity of the pot is 44 liters.