A 180-metre long train takes 25 seconds to cross a platform. If the speed of the train is 72 km/h, then find the length of the platform.

Ajay invested Rs. 6,000 at compound interest (compounded annually) of 30% p.a. for ‘n’ years. If he earned an interest of Rs. 4,140, then find the value of ‘n’.

Income of ‘A’ is 60% more than expenditure of ‘B’ which is equal to Rs. 300. If the savings of ‘A’ is equal to 50% of the expenditure of ‘B’ then find the expenditure of ‘A’.

Present age of ‘A’ is 40% more than that of ‘B’. If 12 years ago from, ‘A’ was twice as old as ‘B’, then find the present age of ‘B’.

The age of Arjun 4 years ago was 25% more than the present age of Rohan. 6 years hence, the ratio of their ages will be 15:11. Find the difference between their present ages.

The speed of a boat in still water is 2 times more than that of the current. If the boat takes 12 hours to cover 144 km upstream, then find the time taken by the boat to cover 480 km downstream.

What will come in place of the question mark (?) in the following series?

5, 6, 14, 45, ?,925

The following numbers form a series. Find the odd one out.

3, 6, 2, 8, 2.4, 9.6

In a school there are 840 students, and the ratio of the number of boys to girls is 5:2. If 120 boys and 180 girls took admission in the school, then find the new ratio of the number of boys to girls in the school.

Ratio of speed of boat in still water and upstream speed of boat is 6:5, respectively. If downstream speed of boat is 17.5 km/h, then find the upstream distance cover by boat in 4 hours.

Marked price of an article, which is sold after 18% discount, is Rs. 12,300. If profit earned on selling the article is Rs. 996, then find the cost price of article.