Quantitative Aptitude - Arithmetic Ability Questions

The diagonal of a square is equal to the side of an equilateral triangle. If the area of the square is 15√3 sq cm, what is the area of the equilateral triangle?

In a triangle ABC, OB and OC are the bisectors of angles ∠ B and ∠C respectively. ∠BAC = 60°. Then the angle ∠BOC will be

The sum of digits of a two-digit number is 9. When the digits are reversed, the number decreases by 45. Find the changed number.

35% of an alloy was silver. If in the quantity of alloy there was 119 g of silver, what was the quantity of the elements in the alloy?

If  x=2+32-3, then what is the value of x+1/x ?

Working together, pipes A and B can fill an empty tank in 10 hours. They worked together for 4 hours and then B stopped and A continued filling the tank till it was full. It took a total of 13 hours to fill the tank. How long would it take A to fill the empty tank alone?

If a + b = 10 and ab- 13 = -ba - 11, then what is the value of 3ab + 4a2 + 5b2 ?

What is the value of [sin (y – z) + sin (y + z) + 2 sin y]/[sin (x – z) + sin (x + z) + 2 sin x]?