The average height of some girls is 136 cm. When 3 boys, with a total height of 348 cm, are included, the average height if the children becomes 132 cm. How many children are there altogether?
| |
Girls |
Boys |
Total |
| Number |
1 u |
3 |
1 u + 3 |
| Value |
136 |
|
132 |
| Total value |
136 u |
348 |
132 u + 396 |
Total height of the girls
= 1 u x 136
= 136 u
Total height of the children = 136 u + 348
136 u + 348 = 132 u + 396
136 u - 132 u = 396 - 348
4 u = 48
1 u = 48 ÷ 4 = 12
Total number of children
= 1 u + 3
= 12 + 3
= 15
Answer(s): 15
