The average height of some boys is 131 cm. When 3 girls, with a total height of 369 cm, are included, the average height if the children becomes 127 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
131 |
|
127 |
Total value |
131 u |
369 |
127 u + 381 |
Total height of the boys
= 1 u x 131
= 131 u
Total height of the children = 131 u + 369
131 u + 369 = 127 u + 381
131 u - 127 u = 381 - 369
4 u = 12
1 u = 12 ÷ 4 = 3
Total number of children
= 1 u + 3
= 3 + 3
= 6
Answer(s): 6