Which number among the following does not belong to the series 8, 27, 50, 125, 343?

The Ajmer express can move at 45 km./hr. without its rake and the speed is diminished by a constant that varies as the square root of the number of wagons attached. If it is known that with 9 wagons, the speed is 30 km./hr., what is the greatest number of wagons with which the train can just move?

The strength of a school increases and decreases in every alternate year by 10 %. It started with increase in 2000, then the strength of the school in 2003 as compared to that in 2000 was : 

Two years ago, the average age of Ram and Shyam was 26 years. Five years hence, the age of Ram will be 40 years and Shyam is 5 years younger than Mohan, then find the difference between the age of Ram and Mohan.

Some amount out of Rs.7000 was lent at 6% per annum and the remaining at 4% per annum. If the total simple interest from both the fractions in 5 year was Rs.1600, find the sum lent at 6% per annum.

If $$ {3^{4x-y}={3^{x+y}=\sqrt{27}}}$$,  then the value of y is:

One number is 50% less than X and another number is 20 percent less than X. What is the ratio of both the numbers?