Tasks number 4,5,6.

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1) Speed of a current is 1.3 km/h against the current 18.3-1.3=17 2) units of =100kg 6.7 c +584 kg =670+584=1254 602-487=115 3) 1. party-3.7 of cm 2. - 2.8 cm 3.-4.9 cm P=3.7+2.8+4.9=11.4 It should be known! It is classics!
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Answer add