| There are some boys and girls in a room. The square of the number of the girls is less than the square of the number of boys by 28. If there were 2 more girls, the number of boys would have been the same as that of the girls. The total number of boys and girls in the room are |
A) 56
B) 14
C) 10
D) 7
Correct Answer: B
Solution :
| Let the number of boys and girls in the room be x and y, respectively. |
| According to the question, |
| \[{{x}^{2}}-{{y}^{2}}=28\] |
| and \[x=y+2\] |
| \[x-y=2\] |
| Now, \[{{x}^{2}}-{{y}^{2}}=(x-y)(x+y)=2\,\,(x+y)\] |
| \[\Rightarrow \] \[28=2\,\,(x+y)\] |
| \[\Rightarrow \] \[x+y=14\] |
| \[\therefore \]Total number of boys and girls \[=14\] |
You need to login to perform this action.
You will be redirected in
3 sec
