 Hello and welcome to this session. Today I will help you with the following question. The question says, if each edge of a cube is doubled, how many times will its surface area increase? Surface area of cube is equal to 6L square where L is the length of a side of cube. This is the key idea for this question. Let's move on to the solution. Let the side of cube be x units then surface area of cube would be equal to 6x square. If we double the side of the cube, the side of cube would be equal to 2x. Now the new surface area would be equal to 6 2x the whole square. This is equal to 6 multiplied by 4x square which is equal to 24x square. Thus we get the new surface area is equal to 24x square. Now the ratio of the areas would be equal to new surface area upon the old surface area. We have the new surface area is 24x square. This becomes equal to 24x square upon the old surface area which is 6x square. So we get 24x square upon 6x square. Now this x square is cancelled with this x square and we know that 6 4 times is 24. So this is equal to 4 upon 1. Thus we say that surface area will increase 4 times. Hence our final answer is 4 times. So hope you enjoyed the session. Have a good day.