Q6. 
The average of five different positive numbers is 25. $x$ is the decrease in the average when the smallest number among them is replaced by 0. What can be said about $x$? 
A.  $x$ is less than 5 

B.  $x$ is greater than 5 

C.  $x$ is equal to 5 

D.  Nothing can be said 
Q7. 
Three math classes: $X, Y$, and $Z$, take an algebra test. The average score in class $X$ is 83. The average score in class $Y$ is 76. The average score in class $Z$ is 85. The average score of all students in classes $X$ and $Y$ together is 79. The average score of all students in classes $Y$ and $Z$ together is 81. What is the average for all the three classes? 
A.  81 

B.  81.5 

C.  82 

D.  84.5 
Q8. 
In 2011, the arithmetic mean of the annual incomes of Ramesh and Suresh was Rs. 3800. The arithmetic mean of the annual incomes of Suresh and Pratap was Rs. 4800, and the arithmetic mean of the annual incomes of Pratap and Ramesh was Rs. 5800. What is the arithmetic mean of the incomes of the three? 
A.  Rs. 4000 

B.  Rs. 4200 

C.  Rs. 4400 

D.  Rs. 4800 
Q9. 
In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun? 
A.  67 kg. 

B.  68 kg. 

C.  69 kg. 

D.  Data inadequate 
Q10. 
A student finds the average of 10 positive integers. Each integer contains two digits. By mistake, the boy interchanges the digits of one number say ba for ab. Due to this, the average becomes 1.8 less than the previous one. What was the difference of the two digits $a$ and $b$? 
A.  8 

B.  6 

C.  2 

D.  4 