The average height of a group of boys was 168 cm. After 4 girls with a total of 732 cm joined the group, the average height of all the students increased to 173 cm.
- What was the average height of the girls?
- How many boys were there in the group?
|
Boys |
Girls |
Students |
Number |
1 u |
4 |
1 u + 4 |
Value |
168 |
? |
173 |
Total value |
168 u |
732 |
173 u + 692 |
(a)
Average height of girls
= 732 ÷ 4
= 183 cm
(b)
Total height of students
= 173(1 u + 4)
= 173 u + 692
Total height of boys and girls = 168 u + 732
173 u + 692 = 168 u + 732
173 u - 168 u = 732 - 692
5 u = 40
1 u = 40 ÷ 5 = 8
Number of boys = 8
Answer(s): (a) 183 cm; (b) 8