The average height of some boys is 131 cm. When 3 girls, with a total height of 333 cm, are included, the average height if the children becomes 125 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
131 |
|
125 |
Total value |
131 u |
333 |
125 u + 375 |
Total height of the boys
= 1 u x 131
= 131 u
Total height of the children = 131 u + 333
131 u + 333 = 125 u + 375
131 u - 125 u = 375 - 333
6 u = 42
1 u = 42 ÷ 6 = 7
Total number of children
= 1 u + 3
= 7 + 3
= 10
Answer(s): 10