In an examination series, which consists of 5 exams, Arvind scored an average of 60 marks in the first 3 exams and an average of 70 in the last 4 exams, what is the average score of Arvind for the first and last two exams if his average scores of all the five exams are 65?

• 63.33
  let exams be a,b,c,d,e
  given a+b+c/3=60=>a+b+c=180.........(1)
  b+c+d+e/4=70=>b+c+d+e=280...........(2)
  a+b+c+d+e/5=65=>a+b+c+d+e=325.......(3)
  by calculating 2 and 3 we get a=45
  calculating 1 and 3 we get d+e=145
  then average of first and last two exams =a+d+e/3=>45+145/3=>190/3=63.33
  
• 10 years agoHelpfull: Yes(2) No(0)
• 30 is the answer
  
  
  Supposing the exams to be a,b,c,d,e
  
  acc. to ques.
  
  (a+b+c)/3=60
  => a+b+c=180 -----eq.1
  
  and
  
  (b+c+d+e)/4=70
  => b+c+d+e=280 -----eq.2
  
  and
  
  (a+b+c+d+e)/5=65
  putting the value of b+c+d+e
  
  => a+280=325
  => a=325-280
  => a=45
  
  putting the value of a in eq.1,we get
  
  => 45+b+c=180
  => b+c=135
  
  putting the value of b+c in eq.2
  
  => 135+d+e=280
  => d+e=45
  
  now, we need to find the average of a,d,e
  
  => (a+d+e)/3 = (45+45)/3 = 90/3 = 30
• 10 years agoHelpfull: Yes(1) No(2)
• 103.33
  by solving these 3 eqns:
  (e1+e2+e3+e4+e5)/5=65
  (e1+e2+e3)/3=60
  (e2+e3+e4+e5)/4=70
  find (e1+e4+e5)/3
• 10 years agoHelpfull: Yes(0) No(2)