The average of 12 number is 42. If a 13th number is added, then the average becomes 44. What is the 13th number?

Directions : What should come in place of the question mark (?) in the following number series? 

19 38 ? 228 684 1368 

Sujatha sold 75% of her goods at a profit of 24% and the remaining at a loss of 40%. What is her gain/loss percentage on the whole transaction?

A person goes to his office by scooter at the speed of 80 km/hr and reaches 60 minutes earlier. If he goes at the speed 50 km/hr, then he reaches 48 minutes late. What will be the speed of the scooter to reach on the usual time?

A, B, C completes 37.5%, 44.44%, 66.66% of a work in 9 days, 8 days, 8 days respectively. Then find how many days they take to complete 65% of work together? 

Alcohol and water in two vessels A and B are in the ratio 5:3 and 5:4 respectively. In what ratio, the liquid of in both the vessels be mixed to obtain a new mixture in vessel C in the ratio 7:5?

Which of the following fractions is greater than $$ {3\over 4}$$  and less than $$ {5\over 6}$$?

Akshay has 30 articles, each having the same cost price. He marked the price of each article at 30% above its cost price. He sold 15 of the articles at a discount of 20% each, and the remaining 15 articles at a discount of 10% each, thereby gaining a total profit of ₹630. What was the cost price of each article?