X, Y and Z jump forward 4', 6' and 5', respectively. At 8 AM, they all land on mark 199'. How many times will they all land on the same mark (need not be at the same moment) between mark 195' and 1000', if all of them cross mark 1000' by 9 AM?

उत्तर देखें और व्याख्या

उत्तर: (D) 14

व्याख्या

Common landing marks are 199 + 60k (LCM of 4, 6, 5 = 60). 199 + 60k ≤ 1000 gives k = 0 to 13, i.e. 14 marks.