Question
A box contains 'y' blue balls and 4 yellow balls. If the
probability of getting a blue ball is 2/3, then find the probability of getting different coloured balls when two balls are drawn randomly from the box.Solution
Total number of balls in the box = y + 4
So, y/(y + 4) = 2/3
Or, 3y = 2(y + 4)
Or, 3y = 2y + 8
So, y = 8
Total balls = 8 + 4 = 12
Desired Probability = (8C1 × 4C1)/12C2 = (8 × 4)/(12 × 11/2) = 32/66 = 16/33
625, 250, 100, 40, 16, 6
Find the wrong number in the given series.
2827, 2863, 2811, 2867, 2819, 2871
Find the wrong number in the given number series.
 289, 274, 260, 247, 235, 225
556, 547, 483, 458, 242, 196
213, 215, 225, 257, 313, 393
164, 160, 172, 136, 188, 128
Find the wrong number in the given number series.
237, 526, 165, 608, 77, 702
128, 173, 196, 189, 176, 133
12, 14, 18, 26, 38, 64
- In the given number series, find the wrong number.
1, 4, 9, 16, 25, 38, 49