Pete’s plane from Melbourne to Canberra leaves at the same time as Don’s plane from Canberra heads toward Melbourne. The wind current is around 5mph and is travelling against the Don’s plane. Both planes are travelling at 120 miles per hour relative to the wind (not the ground). If the distance between the two cities is 300 miles, how long will it take for the two planes to meet?
Answer: Well done to the following readers who gently landed on the correct answer, 75 minutes: Bharat B Sharma, Sr V.P. Product Development & Technical Service (Elastomers), Reliance Industries Ltd, Vadodara, Gujarat, India; Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; John Bowen, consultant, Bromsgrove, UK; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; John D Burrows, (details not supplied); Fariha Rashid, marketing analyst, Kraton Polymers LLC , Houston, Texas; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; Ramasubramanian P, manager, marketing – mixer and LTKMPL products, rubber processing machinery, Larsen & Toubro Ltd, Vedal Village, Kanchipuram, Tamil Nadu, India.
As Bharat B Sharma neatly worked out:
1.25 Hours (or 75 minutes)
Both planes speed== 120mph
Dons’ plane speed—120-5mph== 115 mph
Pete’s plane speed – 120+5mph== 125 mph.
Time when both plane will meet
115xt + 125xt = 300 (total distance)
T= 1.25 hours (75 minutes)