A) \[10:3\]
B) 4 : 9
C) 5 : 8
D) 6 : 7
Correct Answer: B
Solution :
| \[\mu =\frac{1+3+8+x+y}{5}\] |
| \[25=12+x+y\] |
| \[\Rightarrow \] \[x+y=13\] |
| \[{{\sigma }^{2}}=\frac{\sum{{{({{x}_{i}}-\mu )}^{2}}}}{N}\] |
| \[9.2=\frac{1+9+64+{{x}^{2}}+{{y}^{2}}}{5}-25\] |
| \[34.2\times 5=74+{{x}^{2}}+{{y}^{2}}\] |
| \[171=74+{{x}^{2}}+{{y}^{2}}\] |
| \[97={{x}^{2}}+{{y}^{2}}\] | ? (2) |
| \[{{(x+y)}^{2}}={{x}^{2}}+{{y}^{2}}+2xy\] | |
| \[169-97=2xy\] | |
| \[\Rightarrow \] xy = 36 | |
| T = 4, 9 | |
| So, ration is \[\frac{4}{9}or\frac{9}{4}.\] | |
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