21. Consider a class of 23 students. The average age of a student in the class is 12 years. If the age of the teacher is also included, then the average age of the class is increased by 7 Months. What is the age of the teacher ?
24 years
26 years
23 years
None of the abov
22. Suppose there are 6 runners in a race. In how many different orders can these 6 runners finish the race if no ties are allowed ?
120
720
6
None of the above
23. Ramesh saves 25% of his salary. His income is increased by 25% and he increases his expenditure by 10%. Find the percentage increase in his savings.
30%
50%
70%
24. In a school library, science books and arts books are present in the ratio 8 : 7. If 150 more books of arts are added in the library then the ratio becomes 7 : 8. What is the number of science books present in the library?
500
560
700
850
25. A boy purchased some chocolates for ₹600. He could have purchased 5 more chocolates if each chocolate was cheaper by ₹20. The number of chocolates purchased was
10
15
25
30