Question
A bag contains 25 white and some black balls. If the
probability of drawing a black ball from the bag is 1.4 times that of drawing a white ball, find the number of black balls in the bag.Solution
Given, Number of white balls = 25 Let x be the number of black balls. Total number of balls in the bag = 25 + x Also, the probability of drawing a black ball from the bag is 1.4 times that of drawing a white ball. ⇒ x/(25 + x) = 1.4[25/(25 + x)] ⇒ x = 35 Hence, the number of black balls in the bag = 35.
612, 487,?, 396, 388, 387
Find the missing number in the given number series.
1, 2, 6, 24, 120, ?What will come in place of the question mark (?) in the following series?
36, 85, ?, 230, 330, 451
Find the missing term in the series:
2, 5, 11, 23, 47, ?
What will come in place of the question mark (?) in the following series?
400, 841, 1202, ?, 1716, 1885
44   45    41   50    ?      59    23
...221, 100, 0, -81, ?
...900 Â Â Â 90Â Â Â 18Â Â Â ? Â Â Â Â 2.16Â Â Â Â 1.08
16, 20, 11, 27, ?, 38
37, 57, 82, ?, 147, 187
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