Question
Which of the following is not a chemical
change?Solution
Glowing of a platinum wire is a physical change because it involves only a change in state (heat-induced incandescence) without any change in the chemical composition. The rest involve chemical reactions leading to the formation of new substances.
The average of 10 numbers is 102. The average of the first 5 numbers is 78 and the average of the last 4 numbers is 46. What is the 6th number?
A car covers a distance of 60 km at a consistent speed. If the car's speed is increased by 8 km/h, it would take 2 hours less to travel the same distanc...
The average cost price of 12 pens (having equal cost price) decreased by Rs.2, when one of the pen is replaced by a new pen having cost price of Rs.80. ...
The average marks of all the students decreased by 2 when it was found that marks of one of the student were wrongly interpreted as 80 instead of 40. Fi...
The average of six numbers is 8. When three new numbers are included in such a way that the first number is  twice the second and second number is thri...
A bag contains 6 red, 10 yellow, and 14 black balls. If 2 balls are picked at random without replacement, find the probability that the first ball is re...
The average age of 14 girls is 42 years. If the age of two more girl is added the average decreases by one and a half year. What is the sum of the age o...
The average number of coins distributed among five friends is 15. If each friend received 1 coin more than the friend before, then find the highest numb...
There are three distinct numbers ‘u’, ‘v’ and ‘w’. If, u = 240, (u + v) = 540 and (w – v) = 60, then find the average of u, v and w.
...- The average of 30 numbers is 72. If the average of the first 12 numbers is 60 and the average of the last 19 numbers is 80, find the 12th number.
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