How to color the diya #shorts

How does a concave lens help to correct the short sightedness in a person?

How many of the following gives color to the flame test Li,Be,Na,Mg,Ca,Sr,Ba,K,Rb,Cs

A box contains 6 balls which maybe all of different colors or three each of two colors or two each of three different colors.The no of ways of selecting 3 balls from the box is

There are four balls of different colors and four boxes of colors same as those of the balls. Find the number of ways in which the balls, one in each box,could be placed in such a way that a ball does not go to box of its own color.

There are four balls of different colors and four boxes of colors same as those of the balls. Find the number of ways in which the balls, one in each box, could be placed in such a way that a ball does not go to box of its own color.

The color of 'C' is

The color of B is

80 colored caps