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The average age of 30 students in a class is 12 years. The average age of a group of 5 of the students is 10 years and that of another group of 5 them is 14 years. The average age of the remaining students is ?
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- 8 years
- 10 years
- 12 years
- 14 years
Correct Option: C
Let average of the remaining student be y.
Then from questions ( 5 x 10 ) + ( 5 x 14) + 20y = 30 x 12
⇒ 50 + 70 + 20y = 360
⇒ 20y = 360 – 120
⇒ 20y = 240
⇒ y = 12.
