The diameters of two circles are 12 cm and 20 cm, respectively and the distance between their centres is 16 cm. Find the number of common tangents to the circles.

In a school, $${3\over 8}$$ of the number of students are girls and the rest are boys. One-third of the number of boys are below 10 years and $${2\over 3}$$ of the number of girls are also below 10 years. If the number of students of age 10 or more years is 260, then the number of boys in the school is:

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

141, 156, 147, 162, 153, 165, 159

An observer who is 1.62-meter-tall is 45 meters away form a pole. The angle of elevation of the top of the pole from his eyes is 30°. The height ( in meter) of the pole is closet to:

A sector area of 4%   is removed from a circular sheet of paper of diameter 50 cm, If the remaining part is used to make a conical surface , then the ratio of radius and height of the-

A whole number is added to 50 and the same number is subtracted from 50. The sum of the resulting numbers is 

Rehman walks at 8 km/hr and Roma cycles at 13 km/hr towards each other. What was the distance between them when they started if they meet after 36 minutes?

Shashi sells two articles for ₹5,000 each with no loss and no profit in the overall transaction. If one article is sold at $$16{2\over 3}\%$$loss, then the other is sold at a profit of: