The average height of 25 boys is 1.4 m. When 5 boys leave the group, then the average height increases by 0.15 m. What is the average height of the 5 boys who leave? (a) 0.8 m    (b) 0.9 m    (c) 0.95 m    (d) 1.05 m

If a 12 years old boy is replaced by a new boy, then the average age of 18 boys increases by 1.5 years. What is the age of the new boy?

The average of 80 boys in a class is 15. The average age of a group of 15 boys in the class is 16 and the average age of another 25 boys in the class is 14. What is the average age of the remaining boys in the class? (a) 14 (b) 14.75 (c) 15.25 (d) Cannot be determined (e) None of these

The height of 5 boys is recorded as , 146cm, 154 cm, 164 cm, 148 cm and 158 cm. What is the average height of all these boys ?

1cm is equal to: 0.1m (b) 0.01m (c) 0.10m (d) 0.001m

The average height of 5 boys is 175 cm. A sixth boy joined the group and the average height of all the boys in the group now increased by one centimeter. The height of the sixth boy is: 5 लड़कों की औसत लंबाई 175 सेमी है | एक छठा लड़का समूह में शामिल हो जाता है तथा सभी लड़कों की औसत लंबाई एक सेमी से बढ़ जाती है | छठे लड़के की लंबाई कितनी होगी ?

A kite is moving horizontally at a height of 151.5 m. If the speed of the kite is 10 m/s, how fast is the string being let out, when the kite is 250 m away from the boy who is flying the kite? The height of the boy is 1.5 m. (A) 8 m/s (B) 12 m/s (C) 16 m/s (D) 19 m/s