Quantitative Aptitude - Arithmetic Ability Questions

If 31x + 31y = 403, then what is the average of x and y?

A wooden bowl is in shape of a hollow hemisphere of internal radius 7 cm and thickness 1 cm. What is the total surface area (in sq.cm) of the bowl? (Take:  = 22/7)

The ten's digit of a 2-digit number is greater than the units digit by 7. If we subtract 63 from the number, the new number obtained is a number formed by interchange of the digits. Find the number.

The average of 12 numbers is 35. If four numbers 20, 27, 15 and 29 are removed then what will be the average of remaining numbers?

A miner sells a diamond to a trader at a profit of 40% and the trader sells it to a customer at a profit of 25%. If the customer pays Rs 56 lakhs to buy the diamond, what had it cost the miner (in Rs lakhs)?

If ABCDEF is a regular hexagon, then what is the value (in degrees) of ∠ADB?

Which of the following statements is not true?

X and Y are the mid points of sides AB and AC of a triangle ABC. If BC+XY=12 units, then BC-­XY is