The average height of some boys is 148 cm. When 3 girls, with a total height of 402 cm, are included, the average height if the children becomes 145 cm. How many children are there altogether?
|
Boys |
Girls |
Total |
Number |
1 u |
3 |
1 u + 3 |
Value |
148 |
|
145 |
Total value |
148 u |
402 |
145 u + 435 |
Total height of the boys
= 1 u x 148
= 148 u
Total height of the children = 148 u + 402
148 u + 402 = 145 u + 435
148 u - 145 u = 435 - 402
3 u = 33
1 u = 33 ÷ 3 = 11
Total number of children
= 1 u + 3
= 11 + 3
= 14
Answer(s): 14