The average of 8 readings is 24.3, out of which the average of the first two is 18.5 and that of next three is 21.2. If the sixth reading is 3 less than seventh and 8 less than eight, what is the sixth reading? 

If α and β are the roots of equation , then what is the equation whose roots are ${α^3}\over{β^2}{β^3}\over{α^2}$$.

How many bricks, each measuring 25 cm x 11.25 cm x 6 cm, will be needed to build a wall of 8 m x 6 m x 22.5 cm?

The length, breadth and height of a room are in the ratio 7:3:1. If the breadth and height are doubled while the length is halved, then by what percent the total area of the 4 walls of the room will be increased?

Directions: Study the information given below and answer the questions that follow.
An article was bought for Rs. 5600. Its price was marked up by 12%. Thereafter it was sold at a discount of 5% on the marked price.

What was the percent profit on the transaction?

Find the HCF of 3341 and 3328.

A man rows from J to K (upstream) and back from K to J (downstream) in a total time of 15 hours. The distance between J and K is 300 km. The time taken by the man to row 9 km downstream is identical to the time taken by him to row 3 km upstream. What is the approximate speed of the boat in still water?

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

1.7 5.4 19.2 80.8 409 ?