The average height of some girls is 130 cm. When 3 boys, with a total height of 354 cm, are included, the average height if the children becomes 127 cm. How many children are there altogether?
|
Girls |
Boys |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
130 |
|
127 |
Total value |
130 u |
354 |
127 u + 381 |
Total height of the girls
= 1 u x 130
= 130 u
Total height of the children = 130 u + 354
130 u + 354 = 127 u + 381
130 u - 127 u = 381 - 354
3 u = 27
1 u = 27 ÷ 3 = 9
Total number of children
= 1 u + 3
= 9 + 3
= 12
Answer(s): 12