In a kilometer race, by how many meters Chandu beats Chand? Statement I : In a kilometer race, Chandu beats Chandan by 100 meters. Statement II : The respective ratio of the speed of Chandan and Chand is 4: 3. Statement III : In a kilometer race, Chandan beats Chand by 150 meters.

Statement I tells us Chandu beats Chandan by 100m. Statement III tells us Chandan beats Chand by 150m. Combining these: Chandu covers 1000m while Chandan covers 900m, and Chandan covers 1000m while Chand covers 850m. In the same time, Chandu's distance to Chand's distance ratio is 1000:850 = 20:17. When Chandu runs 1000m, Chand runs (17/20)*1000 = 850m. So Chandu beats Chand by 150m. Statement I alone is insufficient, Statement III alone is insufficient, but I+III together are sufficient. Statement II (ratio 4:3) is not needed.