Mixture S is 20% oil and 80% material B by weight.
Mixture S is 20% oil and 80% material B by weight. If 2 more kilograms of oil are added to the 8 kilograms mixture S, how many kilograms of mixture S must be added to make a 70% material B in the new mixture?
Answer/Solution
A)6
Steps/Work
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 .
S1=20(initial mix.)
Avg. is what we need..ie 70% of material B means 30% of oil
S2=36(36% of 10 kg mix)
w1/w2=(S2-Avg)/(Avg-S1)
(36-30)/(30-20)
6/10
means for every 10 kg of new mix. we need 6 kg of mix S
Ans A
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 .
S1=20(initial mix.)
Avg. is what we need..ie 70% of material B means 30% of oil
S2=36(36% of 10 kg mix)
w1/w2=(S2-Avg)/(Avg-S1)
(36-30)/(30-20)
6/10
means for every 10 kg of new mix. we need 6 kg of mix S
Ans A