The average weight of the students in four sections A, B, C and D is 55 kg. The average weights of the students A, B, C and D are 45 kg, 40 kg, 75 kg and 85kg respectively. If the average weight of the students of section A and D together is 65 kg and that of B and D together 55 kg, then what is the ratio of the number of students in A and C?

• Since average of B and D is 55, average of A and C should be calculated as:
  55 + avg(A,C) = 55 * 2.
  Therefore avg(A, C) = 55.
  Now, by alligations formula, we can get the ratio as 2:1
• 7 years agoHelpfull: Yes(0) No(1)