A box contains 13 black and 13 white balls. The probability of drawing two balls of the same colour is?
Total number of balls = 13 + 13 = 26 Let S be the sample space. Then, n(S) = number of ways of drawing 2 balls out of 26 = 26C 2 = `(26xx25)/(2xx1)=325` Let E = event of drawing 2 balls of the same color n (E) = 13C 2 + 13C2 = `(13xx12)/(2xx1)+(13xx12)/(2xx1)` = 78 +78 = 156 P (E) = `(n(E))/(n(S))=156/325`
Tap ‘A’ and tap ‘B’ can fill a tank in 40 hours and 36 hours, respectively. If both taps are opened together, then find the time after which tap...
An inlet can fill an empty tank in 6 hours whereas an outlet pipe can empty it in 12 hours. If (N - 1) such outlet pipes having same efficiency and (N +...
Pipe ‘A’ takes 40 minutes to fill a tank. Pipe ‘B’ takes 50 minutes to empty the same tank. If pipe ‘B’ is opened 21...
Pipe ‘A’ can fill a tank in 10 hours while pipe ‘B’ can empty it in 12 hours. They were operated on alternate hours starting with pipe ‘A’. ...
Pipe A and Pipe B together can fill the tank in 15 hours. The capacity of the pipe A is 20% of the capacity of the pipe B. How much time will pipe B alo...
Pipe ‘A’ can fill a tank in 30 hours whereas leak ‘A’ can empty it in 40 hours. If they both operate along with pipe ‘B’, then the given tan...
Pipe M and N can fill a tank together in 25 hours while pipe N alone can fill the tank in 30 hours. Find the time taken by pipe M to fill the tank if it...
Two pipes P1 and P2 can fill a cistern in 12 minutes and 15 minutes respectively. These pipes are opened alternately for 1 minute each, beginning with p...
Pipe ‘A’ can fill a tank in 25 hours while pipe ‘B’ can empty it in 30 hours. They were operated on alternate hours starting with pipe ‘A’. ...
Pipe ‘A’ can fill a tank in 20 hours while pipe ‘B’ takes 32 hours to empty it. Pipe ‘A’ is opened alone when the tank was empty and after 1...
