Quantitative Aptitude - Arithmetic Ability Questions

If the radius of a circle is decreased to 25% of its original value, calculate the percentage decrease in the area of the circle

If 3A = 7B = 13C, then A : B : C is equal to

The zeros of the cubic polynomial 2x3-x2-2x+1 are a, b and c respectively. Find a+b+c :

15% of a number, when added to 30% of another, gives 24% of the sum of the two numbers. The bigger number is 4 more than the smaller one. What are the numbers?

Two trains are moving in the opposite direction at speed of 30 km/hr and 45 km/hr respectively, whose lengths are 450 m and 550 m respectively. What is the time taken (in seconds) by slower train to cross the faster train?

A vendor buys pens at the rate of 4 for Rs 5 and sells at the rate of 4 for Rs 3. What will be the result?

The average age of a class of 6 girls is x years. Four new girls having ages x – 2, x + 2, x + 4 and x + 6 joins the class. What is the new average age (in years) of the class?

If a+b=5 and a­b=3, then the value of (a2+b2) is