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After 25kg of water had been evaporated form a solution of salt and water,which had 20% salt,the remaining solution had 30% salt.Find the weight of the original solution.

After 30kg of water had been evaporated from a solution of salt and water,which had 15% salt,remaining solution had 20% salt.The weight of the original solution was 80backslash kg b.120backslash kg c.90backslash kgd.135backslash kg

Q.N. 45 In a survey of 25 students ,it was found that 15 had taken mathematics , 12 had taken physics and 11 had taken chemistry ,5 had taken mathematics and chemistry, 9 had taken mathematics and physics, 4 had taken physics and chemistry and 3 had taken all the three subjects. write the number of student that had taken (a) at least one of three subjects (b) only mathematics