The average height of a group of girls was 162 cm. After 6 boys with a total of 1050 cm joined the group, the average height of all the students increased to 163 cm.
- What was the average height of the boys?
- How many girls were there in the group?
|
Girls |
Boys |
Students |
Number |
1 u |
6 |
1 u + 6 |
Value |
162 |
? |
163 |
Total value |
162 u |
1050 |
163 u + 978 |
(a)
Average height of boys
= 1050 ÷ 6
= 175 cm
(b)
Total height of students
= 163(1 u + 6)
= 163 u + 978
Total height of girls and boys = 162 u + 1050
163 u + 978 = 162 u + 1050
163 u - 162 u = 1050 - 978
1 u = 72
1 u = 72 ÷ 1 = 72
Number of girls = 72
Answer(s): (a) 175 cm; (b) 72