How many kg of pure salt must be added to 100kg of 10% solution of salt and water to increase it to a 30% solution? Answers:
A) A)6.7
B) B)1.3
C) C)9.6
D) D)12.5
E) E)28.6
Amount salt in 100kg solution = 10*100/100= 
<gadget id="calculator">10*100/100</gadget>
<output>10</output>
10 kg   Let x kg of pure salt be added   then(10+x)/(100+x)=30/100   100+10x=300+3x   7x = 200   x = 28.6   Answer is 28.6
<result>E</result>
How many kg of pure salt must be added to 100kg of 10% solution of salt and water to increase it to a 30% solution?