A) 51.75
B) 51.95
C) 52.25
D) 52.75
Correct Answer: C
Solution :
Here, \[{{n}_{1}}=40,\]\[{{n}_{2}}=35,\]\[{{n}_{3}}=45\]and \[{{n}_{4}}=42\] \[{{\bar{x}}_{1}}=50,\]\[{{\bar{x}}_{2}}=60,\]\[{{\bar{x}}_{3}}=55,\]and \[{{\bar{x}}_{4}}=45,\] \[\therefore \] \[\bar{X}=\frac{{{n}_{1}}{{{\bar{x}}}_{1}}+{{n}_{2}}{{{\bar{x}}}_{2}}+{{n}_{3}}{{{\bar{x}}}_{3}}+{{n}_{4}}{{{\bar{x}}}_{4}}}{{{n}_{1}}+{{n}_{2}}+{{n}_{3}}+{{n}_{4}}}\] \[=\frac{40\times 50+35\times 60+45\times 55+42\times 45}{40+35+45+42}\] \[=\frac{2000+2100+2475+1890}{162}\] \[=\frac{8465}{162}=52.25\] \[\therefore \]Overall average of marks per student =52.25
You need to login to perform this action.
You will be redirected in
3 sec
