Quantitative Aptitude - Arithmetic Ability Questions

If x - √x = 20; Find the value of √x.

What is the digit in unit's place of the product 51 x 52 x 53 ...... 59?

Two pipes, when working one at a time can fill a cistern in 2 hrs and 3 hrs, respectively while a third pipe can drain the cistern empty in 6 hrs. All the three pipes were opened together when the cistern was 1/6 full. How long will it take for the cistern to be completely full?

In ΔPQR, ∠QPR = 45° and the bisectors of ∠PQR and ∠PRQ meets at O. What is the value (in degrees) of ∠QOR?

Dodecahedron has 30 edges. How many vertices does it have?

Two trains are moving in the same direction at the speed of 42 km/hr and 84 km/hr, their lengths are 320 metres and 380 metres respectively. What is the time taken (in seconds) by faster train to cross the slower train?

The age of A is three times the age of B. What is the ratio of the age of B to the age of A?

Find the greatest number which on dividing 1580 and 3800 leaves remainders 8 and 1 respectively.