The average height of some boys is 127 cm. When 3 girls, with a total height of 306 cm, are included, the average height if the children becomes 122 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
127 |
|
122 |
Total value |
127 u |
306 |
122 u + 366 |
Total height of the boys
= 1 u x 127
= 127 u
Total height of the children = 127 u + 306
127 u + 306 = 122 u + 366
127 u - 122 u = 366 - 306
5 u = 60
1 u = 60 ÷ 5 = 12
Total number of children
= 1 u + 3
= 12 + 3
= 15
Answer(s): 15