AC is a chord of circle whose centre is at O. If B is any point on the arc AC and ∠OCA=20⁰ , then the magnitude of ∠ABC is

Present ages of Parth and Abhishek are in the ratio of 5 : 4 respectively. Three years hence, the ratio of their ages will become 11 : 9 respectively. What is Abhishek 's present age in years?

The length of a plot is five times its breadth. A playground measuring 245 square metres occupies half of the total area of the plot. What is the length of the plot?

If the diagonals of a rhombus are 24cm and 10cm, then the perimeter of the rhombus is ___________.

The sum of ages of mother and son is 47 years. Before 10 years, the product of their ages is 50. The difference between the ages of mother and a son is –

If p : q : r = 1: 2: 4, then $$\sqrt{5p^{2}+q^{2}+r^{2}}$$ is equal to 

The average of 30 numbers is 40 and that of the other 40 numbers is 30. The average of all the numbers is-

A and B together can do a piece of work in 12 days, A and C together can do the same work in 15 days. If B and C together can do the same work in 20 days, then in how many days A, B and C together can complete the same work?