The average of six numbers is 30. If the average of first four is 25 and that of last three is 35, the fourth number is :

a. 25
b. 30
c. 35
d. 40

• sum of six no is 6*30= 180
  sum of 4 no=4*25=100
  remaining 2 no = 80
  sum of 3 no=3*35=105
  sum of 3 no- remaining two no= 105-80=25 is the ans
  
• 11 years agoHelpfull: Yes(26) No(2)
• 1+2+3+4+5+6= 180
  4+5+6=105
  1+2+3=105-180 = 75
  w.k.t
  1+2+3+4 =100
  4= 100- 75
  4= 35 ans
• 11 years agoHelpfull: Yes(5) No(20)
• ANS-25
  EASY WAY-4*25+3*35-6*30=25
• 10 years agoHelpfull: Yes(4) No(1)
• sum of 6 no. 180
  sum of 4 no.100
  sum of 3 no.105
  100+105=205
  205-180=25
• 9 years agoHelpfull: Yes(4) No(2)
• Required 4th number is (25*4 + 35*3) - 180 = (100 + 105) - 180 = 205-180 =25.
• 8 years agoHelpfull: Yes(0) No(0)
• 45
  (4*25)+35+x=(6*30)
  x=45
• 7 years agoHelpfull: Yes(0) No(0)
• sum of 6*30=180
  sum of 4 no (4*25=100)
  so remaining 2 no=(180-100=80)
  sum of 3 no (3*35=105)
  so 4th no = 105-80=25 ans
• 6 years agoHelpfull: Yes(0) No(0)