Quantitative Aptitude - Arithmetic Ability Questions

A and B take part in 100 m race. A runs at 5 kmph. A gives B a start of 8 m and still beats him by 8 seconds. The speed of B is:

Of the four numbers, whose average is 60, the first is one-fourth of the sum of the last three. The first number is :

A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls, the volume of the hall is:

The two lines 3x - 8y = 16 and 2x + 4y = 6 intersect at (a,b). Find the value of a2-4b2

Select the missing number based on the given related pair of numbers.

158 : 384 :: 140 : ___

 The average age of 8 men is increased by years when two of them whose ages are 21 years and 23 years are replaced by two new men. The average age of the two new men is :

A car owner buys petrol at Rs 7.50, Rs. 8 and Rs. 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if he spends Rs. 4000 each year ?

3 men, 4 women and 6 children can complete a work in 7 days. A woman does double the work a man does and a child does half the work a man does. How many women alone can complete this work in 7 days  ?