The first plane took off with a speed 500km/h, in 2 hours in the same direction with a speed 700km/h the second took off. what distance between them in 3 h will be?

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500*2 = 1000 km flew by prevy 700-500 = 200 km/h - rapprochement speed. 200*3 = 600 km - on will approach so many. 1000-600 = 400 km - distance between them. Km plane-500 speed / chcherez 2 hours the 2nd plane with a speed of 700 km / chresheniye: 1) 2+3=5(ch) - was in way 1 samolyot2) 500*5=2500 (km) - flew by 1 samolyot3) 700*3 =2100 (km) - flew by 2 samolyot4) 2500-2100=400 (km) - the distance between planes through 3 chasaotvt: 400 kilometers will be between planes in 3 hours.
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