tcs - suresh raina and gautam gambhir after a scintillating ipl match decide to travel by cycle to their respective villages both of them start their journey travelling in opposite directions each of their speeds is 6 miles per hour when they are at a distance - skillgun

Since Raina and Gambhir are travelling in opposite directions, Gambhir's Relative speed with respect to Raina's = Speed of Raina + Speed of Gambhir = 6 + 6 = 12 miles per hour.
Now housefly starts from Raina's cycle and travels towards Gambhir's cycle at 17 miles per hour.
Relative speed of housefly with respect to Gambhir = Speed of housefly with respect to Raina - Speed of Gambhir with respect to Raina = 17 - 12 = 5 miles per hour
Time taken for housefly to reach Gambhir = Distance to catch up / Relative speed of housefly with respect to Gambhir = 50/5 = 10 hours.