An envelope surrounds the virus in

The gaseous envelope surrounding the earth is called ……….

The gaseous envelope which surrounds the Earth is called as...

There are 3 letters and 3 addressed envelopes coorresponding to their . The number of ways in which the letters be placed in the envelopes so that no letter is in the right envelope is

Name the Protein coat which surrounds the viral nucleic acid, core of virus.

A box contains 40 envelopes of which 25 are ordinary (not meant for air mail ) and 16 are unstamped, while the number of unstamped ordinary envelopes is 10. What is the probability that an envelope chosen from the box is a stamped air mail envelope?

There are n letters and n corresponding envelopes. In how many ways the letters can be placed in the enveloped (one letters in each envelope) so that no letter is put in the right envelop.

The number of ways of 5 letters put in 5 addressed envelopes so that one letter is in right envelop and all the remaining are placed in wrong envelopes is