Mixture V is 20% oil and 80% material B by weight. If 2 more kilograms of oil are added to the 8 kilograms mixture V, how many kilograms of mixture V must be added to make a 70% material B in the new mixture? Answers:  A) A)6  B) B)7  C) C)8  D) D)9  E) E)10
Can be done with weighted avg method.   if 2 kg more of oil is added to 20% oil of 8 kg mix,then a 10kg of mix will have 3.6kg (or 36%) of oil .   V1=20(initial mix.)   Avg. is what we need..ie 70% of material B means 30% of oil   V2=36(36% of 10 kg mix)   w1/w2=(V2-Avg)/(Avg-V1)   (36-30)/(30-20)   6/10   means for every 10 kg of new mix. we need 6 kg of mix V   6ns 6
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Mixture V is 20% oil and 80% material B by weight. If 2 more kilograms of oil are added to the 8 kilograms mixture V, how many kilograms of mixture V must be added to make a 70% material B in the new mixture?