The average height of some boys is 132 cm. When 3 girls, with a total height of 324 cm, are included, the average height if the children becomes 124 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
132 |
|
124 |
Total value |
132 u |
324 |
124 u + 372 |
Total height of the boys
= 1 u x 132
= 132 u
Total height of the children = 132 u + 324
132 u + 324 = 124 u + 372
132 u - 124 u = 372 - 324
8 u = 48
1 u = 48 ÷ 8 = 6
Total number of children
= 1 u + 3
= 6 + 3
= 9
Answer(s): 9