The average height of a group of boys was 156 cm. After 6 girls with a total of 1056 cm joined the group, the average height of all the students increased to 166 cm.
- What was the average height of the girls?
- How many boys were there in the group?
|
Boys |
Girls |
Students |
Number |
1 u |
6 |
1 u + 6 |
Value |
156 |
? |
166 |
Total value |
156 u |
1056 |
166 u + 996 |
(a)
Average height of girls
= 1056 ÷ 6
= 176 cm
(b)
Total height of students
= 166(1 u + 6)
= 166 u + 996
Total height of boys and girls = 156 u + 1056
166 u + 996 = 156 u + 1056
166 u - 156 u = 1056 - 996
10 u = 60
1 u = 60 ÷ 10 = 6
Number of boys = 6
Answer(s): (a) 176 cm; (b) 6