A vendor sells potatoes at a cost price, but he mixes some rotten potatoes and thereby gains 25%. The percentage of rotten potatoes in the mixture is? 

Directions: Find the wrong number in the following number series:

2, 6, 10, 19, 36, 69, 134

A secant PAB is drawn from an external point P to the circle with centre O, intersecting it at A and B. If OP = 17 cm, PA = 12 cm and PB = 22.5 cm, then the radius of the circle is:

Find the cube root of $$ ^{3}\sqrt{-13824}$$.

Directions: The line graph shows the number of work visas issued by a country in each year from 2011 to 2016. Study the diagram and answer the following questions . 

What is the total number of visas issued from 2012 to 2015 ? 

The length of a rectangle is increased by 60% then by how much % should the breadth be reduced so that its area does not change?

The present age of A and B are in the ratio 5: 4. After 10 years the ratio becomes 7: 6. Find the present age of A.

The area of a triangle is 96 cm² and the ratio of its sides is 6 : 8 : 10. What is the perimeter of the triangle?