To answer this question use the rule of 72. It tells you the time it will take for an amount or quantity to double

Which is basically n = 72/x , n = number of years, x = growth rate

It can be used for relative growths as well. Just like here you have been given the relative growth of product b vs all the products.

Here product b accounts for roughly 25% (34/125) of all the products, for it to become 50% of all the products it has to double. Hence

n = 72/(10-5){the difference b/w growths} = ~14 years hence the correct option is C 15 years the mimimum time required to double

To answer this question use the rule of 72. It tells you the time it will take for an amount or quantity to double

Which is basically n = 72/x , n = number of years, x = growth rate

It can be used for relative growths as well. Just like here you have been given the relative growth of product b vs all the products.

Here product b accounts for roughly 25% (34/125) of all the products, for it to become 50% of all the products it has to double. Hence

n = 72/(10-5){the difference b/w growths} = ~14 years hence the correct option is C 15 years the mimimum time required to double