A vessel contains 5 red, ‘x’ green and 3 blue ribbons. If two ribbons are drawn from the vessel randomly, then the probability of getting a red and a green ribbon is 3/11. Find the value of x.
Total number of ribbons = (x + 8) According to question; (xC1 × 5C1)/(x + 8)C2 = 3/11 2 × 5x/(x + 8)(x + 7) = 3/11 110x = 3 × (x2 + 15x + 56) 110x = 3x2 + 45x + 168 3x2 – 65x + 168 = 0 3x2 – 9x – 56x + 168 = 0 3x(x – 3) – 56(x – 3) = 0 (3x – 56)(x – 3) = 0 So, x = 56/3 or x = 3 Since number of ribbons can’t be in fraction Therefore, x = 3
Study the given pattern carefully and select the number that can replace the question mark (?) in it.
4 7 6
15 ? 21
44 68 60
27 28 37 62 111 ?
89 78 74 67 63 ?
? 190 210 238 274 318
...14 26 50 98 194 ?
...77 ? 190 257 331 412
...13 24 75 134 447 892
...92, 51, 21, 13.5, x, 4.25
find the value of (10x + x -5)?
7 14 42 168 840 ?
...Direction: Which of the following will replace ‘?’ in the given question?
2, ‘?’, 46, 136, 311, 605, 1086
