How many kg of pure salt must be added to 100kg of 10% solution of salt and water to increase it to a 15% solution?
Choose the most appropriate option
A) 5.8 B) 1.3 C) 9.6 D) 12.5 E) 7.9

Rationale: amount salt in 100 kg solution = 10 * 100 / 100 = 10 kg let x kg of pure salt be added then ( 10 + x ) / ( 100 + x ) = 15 / 100 200 + 20 x = 300 + 3 x 17 x = 100 x = 5.8 answer is a
Answer: A