The average height of 30 boys out of a class of 50, is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is :

a. 161
b. 162
c. 163
d. 164

• (30x160+20x165)/50=162
• 11 years agoHelpfull: Yes(6) No(2)
• Since avg of 30 boys=160 and avg of 20=165....
  Total height=((30x160)+(20x165))/50=162.
  I.e height of 50 boys is 162 cm
• 7 years agoHelpfull: Yes(2) No(1)
• the answer is 162 cm.
  because
  average height of whole class is (the sum of the heights of the whole class)/number of humans
  1.sum of heights of 30 boys is average height of 30 boys * 30
  2.sum of heights of remaining boys is average heights of remaining boys*(50-30)
  sum of heights of all boys is 1. + 2.
  average heights of all boys in the class is = sum of heights of all boys/50
  =162cm
• 3 years agoHelpfull: Yes(0) No(0)