Total balls = 4 + 6 + 7 = 17∴ n(S) = 17C1 = 680Two red balls can be selected from four red balls in 4C2 = 6 ways.and the third ball can be selected from the remaining 13 balls in 13C1 = 13 ways.∴ P (E) = 13x6/680 = 39/340
Let the no. be xTherefore 68x / 100 - 35x / 100 = 1216 Therefore x = 1216 x 100 / 33Therefore 28% of x = 28x / 100 = 1216 x 100 / 33 x 28 / 100= 1216 x 100 x 28 / 33 x 1/100 = 1031.75