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There are two groups A and B of a class, consisting of 42 and 28 students respectively. If the average weight of group A is 25 kg and that of group B is 40 kg, find the average weight of the whole class.
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- 69 kg
- 31 kg
- 70 kg
- 30 kg
- 69 kg
Correct Option: B
| Required average weight = | |
| 42 + 28 |
| Required average weight = | |
| 70 |
| Required average weight = | |
| 70 |
Required average weight = 31 kg
Second method to find the required average ,
Here, n1 = 42, a1 = 25
n2 = 28, a2 = 40
| Average = | |
| n1 + n2 |
| Average weight = | |
| 42 + 28 |
| Average weight = | |
| 70 |
| Average weight = | = 31 kg | |
| 70 |
