The average height of some girls is 127 cm. When 3 boys, with a total height of 309 cm, are included, the average height if the children becomes 118 cm. How many children are there altogether?
|
Girls |
Boys |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
127 |
|
118 |
Total value |
127 u |
309 |
118 u + 354 |
Total height of the girls
= 1 u x 127
= 127 u
Total height of the children = 127 u + 309
127 u + 309 = 118 u + 354
127 u - 118 u = 354 - 309
9 u = 45
1 u = 45 ÷ 9 = 5
Total number of children
= 1 u + 3
= 5 + 3
= 8
Answer(s): 8