2туриста вышли из двух пунктов навстречу к друг другу один шел 8 км.ч. а другой на велосипеде на 12 км.ч больше какое расстояние между ними в начале если встретются через 3 часа

1)8*3=24(км)-расстояние пешком 2)12+8=20(км)-скорость на велосипеде 3)20*3=60(км)-расстояние на велосипеде 4)60+24=84(км)-расстояние обоих

84 км 8*3+3*(12+8)=84 км

The black sea is very inviting for families with children. summer is infrequent storm - this is because the black sea is small, the wave can't get the full effect, here there are hardly any threat to human sea animals. water contains little salt, and it does not irritate the eyes. the black sea is useful for teaching swimming. the child will give pleasure to study the underwater world, if you teach him to dive. the black sea receives the waters of many rivers, so the salinity of the surface waters is relatively small. unfortunately, low salinity reduces the diversity of the fauna of the black sea, the inhabitants of the seas and oceans can not tolerate a salinity of less than 20 g/l. the surface layer of the black sea water - less sole and its water is more easy, close in temperature to the air; in the summer it is well heated in the winter - cooled. all others - deep waters of the black sea: from 50-100m to the very bottom, lying at a depth of two kilometers - more salty and heavy, the temperature is always constant: 9c. is the property of waters of the black sea. freshened surface water is not mixed with more saline deep waters, which prevents the penetration of oxygen into the depths of the black sea. and at the depth of 200 meters the oxygen in the water of the black sea is almost absent, animals and plants there can not live, but live bacteria that decompose descending from the top of the remains of animals and vegetation and produce this hydrogen sulfide. the black sea is one of the youngest seas of the earth 8,000 years ago it was the lake, its shores and the ecosystem is still in the dynamics, changing sea levels, changing flora and fauna of the black sea - new marine non-indigenous species, and some of those that lived here before is gone. for example, many of the black sea mollusks whose shells we find on the beaches, today is already extinct: they destroyed one of the most ruthless predators of the black sea, the pacific, the introduced gastropod mollusk brine. rivers flowing into the black sea, give food its flora and fauna, they are in their waters a lot of nutrients, these nutrients and sunlight give rise invisible to us unicellular algae, phytoplankton. they can be found in every drop of water at the sea surface and be seen through the microscope. tiny marine plants in the water column - eat microscopic marine animals - zooplankton : elementary - ciliates, amoebae, small crustaceans, and other marine invertebrates and their larvae, fish larvae; this ecological group of marine organisms and includes some large animals: large jellyfish and grabdevice is also plankton. wildlife black sea is amazing. you can wander through the knee-deep water on the sandy beach and see a lot of informative: crabs, hermit crabs, almost imperceptible bottom fishes of the black sea gobies, sea diamonds and flounder, mullet and mullet, sea mouse, sea cow and sea needle. carefully observe them and try to understand how they live. the most diverse and interesting underwater world of the black sea from the rocky shores. in shallow water - colored multicellular algae of the black sea, running over rocks colorful fish blennies, crabs, sea anemones deeper - a dense jungle of cystoseira - main algae of the black sea in the coastal zone. cystoseira home for fish greenfinches. on the branches of algae slip tiny sea snails and jumping shrimp. in the thick hides of the stone crab is the largest on the black sea, and lives the brightest fish in the black sea - trooper. and on top of czk underwater forest-clad flocks of fish, mullet, mackerel. animals and plants of the black sea is not only large and bright but tiny, hiding among rocks and algae - all interesting, each of them has its place in the life of the sea. deeper - spicery, batfish, a large fish of the black sea slab and marine rock bass, sea carp - lasker and zubarik; on the surface of the stones - cortical animals-epiphytes of sponges, bryozoans, hydroids, polychaetes, ascidians, and other, most unusual, the inhabitants of the black and where the end rocks, and begins expiring in depth, covered with sand, shells and mud shelf of the black sea at that depth, where usually only get divers in cold water live scat thrasher, flounder, turbot, sea cock and prickly shark katran. observing and studying with a child an unusual underwater life of the black sea - you can read about how - in general - life in the seas and oceans