The average height of some boys is 130 cm. When 3 girls, with a total height of 366 cm, are included, the average height if the children becomes 126 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
130 |
|
126 |
Total value |
130 u |
366 |
126 u + 378 |
Total height of the boys
= 1 u x 130
= 130 u
Total height of the children = 130 u + 366
130 u + 366 = 126 u + 378
130 u - 126 u = 378 - 366
4 u = 12
1 u = 12 ÷ 4 = 3
Total number of children
= 1 u + 3
= 3 + 3
= 6
Answer(s): 6