Question
The average height of a group of girls was 122 cm. After 9 boys with a total of 1278 cm joined the group, the average height of all the children increased to 134 cm.
  1. What was the average height of the boys?
  2. How many girls were there in the group?
3 m
(a)

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(b)

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The average height of a group of girls was 122 cm. After 9 boys with a total of 1278 cm joined the group, the average height of all the children increased to 134 cm.
  1. What was the average height of the boys?
  2. How many girls were there in the group?