Quantitative Aptitude - Arithmetic Ability Questions

The average of 5 members of a family is 24 years. If the youngest member is 8 years old, then what was the average age (in years) of the family at the time of the birth of the youngest member?

A cuboid of size 50 cm × 40 cm × 30 cm is cut into 8 identical parts by 3 cuts. What is the total surface area (in cm2) of all the 8 parts?

A taxi going at 90 km/hr takes 35 minutes to travel a certain distance. By how much should it increase its speed (in km/hr) to travel the same distance in 21 minutes?

If a taxi going at 40 km/hr takes 25 minutes to travel a certain distance, by how much should it increase its speed (in km/hr) to travel the same distance in 20 minutes?

Meghnad can do a piece of work in 45 hours. If he is joined by Jayshri, who is 50% more efficient, in what time will they together finish the work?

The effective annual rate of interest corresponding to a nominal rate of 15% per annum payable half-yearly is

What should be the missing digit so that the number 347_547 becomes exactly divisible by 11?

The ratio 1 : 5 can be expressed in decimal as