Question
The average height of a group of boys was 142 cm. After 9 girls with a total of 1422 cm joined the group, the average height of all the students increased to 150 cm.
  1. What was the average height of the girls?
  2. How many boys were there in the group?
3 m
(a)

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(b)

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The average height of a group of boys was 142 cm. After 9 girls with a total of 1422 cm joined the group, the average height of all the students increased to 150 cm.
  1. What was the average height of the girls?
  2. How many boys were there in the group?