Given k = -3. Find the value of $$ {k^3+3k}$$. 

In a company, there are 75% skilled workers and remaining ones are unskilled. 80% of skilled workers and 20% of unskilled workers are permanent. If number of temporary workers is 126, then what is the number of total workers?

The average marks obtained in a class of 50 students is 70%. The average of first 25 is 60% and that of 24 is 80%. What is the marks obtained by the last student?

A can finish work in 18 days and B in 36 days. If they work on it together for 9 days, what percent of work is left?

A semicircle is folded to make a cone. Find the height (in cm) of the cone if diameter of the semicircle is 28 cm?

What is the sum of all three-digit numbers which are divisible by 20?

In a school $${1\over10} $$ of the boys are same in number as $${1\over4}$$ of the girls and  $${5\over8} $$ of the girls are same in number as $${1\over4}$$   of the boys. The ratio of the boys to girls in that school is: 

The distance between two parallel poles is 40√3 m. The angle of depression of the top of the second pole, when seen from the top of first pole, is 30 °. What will be the height of second tower if the first pole is 100m long?