The average height of some boys is 125 cm. When 3 girls, with a total height of 309 cm, are included, the average height if the children becomes 119 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
125 |
|
119 |
Total value |
125 u |
309 |
119 u + 357 |
Total height of the boys
= 1 u x 125
= 125 u
Total height of the children = 125 u + 309
125 u + 309 = 119 u + 357
125 u - 119 u = 357 - 309
6 u = 48
1 u = 48 ÷ 6 = 8
Total number of children
= 1 u + 3
= 8 + 3
= 11
Answer(s): 11