The average height of some girls is 132 cm. When 3 boys, with a total height of 321 cm, are included, the average height if the children becomes 127 cm. How many children are there altogether?
| |
Girls |
Boys |
Total |
| Number |
1 u |
3 |
1 u + 3 |
| Value |
132 |
|
127 |
| Total value |
132 u |
321 |
127 u + 381 |
Total height of the girls
= 1 u x 132
= 132 u
Total height of the children = 132 u + 321
132 u + 321 = 127 u + 381
132 u - 127 u = 381 - 321
5 u = 60
1 u = 60 ÷ 5 = 12
Total number of children
= 1 u + 3
= 12 + 3
= 15
Answer(s): 15
