in a class of 50 students the average age of girls is 12.3 yrs and boys is 12.3 yrs and that of boys is 12.5 yrs . if the average of the class is 12.4 yrs , then the number of boys and girls in the class are ?

• 25 boys & 25 girls
  
  *If the question is like "the average age of girls is 12.3 yrs and boys is 12.5" ,then with boys=b & girls=g
  b+g= 50 ---(i) &
  (12.3b+12.5b)/50=12.5 ---(ii)
  On solving (i) & (ii), b=25, g=25
• 9 years agoHelpfull: Yes(7) No(3)
• Now let no of boys be b and no of girls be g.
  Then (1) total 50 students => b + g = 50.
  
  (2) 12.5b + 12.3g = 12.4*50.
  
  After solving above two equations we get b =25 and g = 25..
• 9 years agoHelpfull: Yes(6) No(2)
• Pl. read in my earlier solution as
  (12.3b+12.5b)/50=12.4 ---(ii)
• 9 years agoHelpfull: Yes(3) No(0)
• Its a simple alligations concept, by solving you get the ratio of boys & girls as 1:1 & hence the total no of boys is 25 & girls is 25.
• 9 years agoHelpfull: Yes(1) No(1)
• Ans: 25 boys and 25 girls
  Sol:let No of girl is X and boy(50-X)
  ((X*12.3)+(50-X))/50=12.4
  after Solving equation, we get
  X=25
• 8 years agoHelpfull: Yes(1) No(0)
• let x be no. of girls
  so no. of boys is 50 - x
  
  equation becomes
  12.3 * x + 12.5 * (50 - x) = 50 *12.4
  makes x = 25
  so no of girls and boys are 25 and 25 respectively
• 4 years agoHelpfull: Yes(0) No(0)