From three fields which area of 74 hectares, 108 hectares, and 48 hectares, collected according to 21 t, 63 t, 18 t of potatoes. To determine by average productivity of potatoes.

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Average yield = all harvest is divisible on all square. 1) 21 + 63 + 18 = 102 t - all harvest 2) 74 + 108 + 48 = 230 hectares - all area 3) 102 t: 230 hectares = 51/115 t/hectare ≈ 0.443 t/hectare = 4.43 c/hectare - OTVETNA 1 field productivity 21/74=0.284 tons from hectare. On the 2nd field productivity 63/108=0.583 tons from hectare. On 1 field productivity 18/48=0.375 tons from hectare. the Average yield is equal (0.284+0.583+0.375)/3=0.414 tons from hectare. Answer: 0.414 tons from hectare.
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