Explanation
Let the total number of yellow roses be $$x$$
Hence, $$\dfrac{1}{7} + \dfrac{4}{7} + x = 1$$
$$\Rightarrow \dfrac{(1 + 4 + 7x) }{7} = 1$$
$$\Rightarrow \dfrac{(5 + 7x) }{ 7} = 1$$
$$\Rightarrow 5 + 7x = 7$$ [ by cross multiplication]
$$\Rightarrow 7x = 7 - 5$$
$$\Rightarrow 7x = 2$$
$$\Rightarrow x = \dfrac{2}{7}$$
$$\therefore $$ The fraction of yellow roses are $$\dfrac{2}{7}$$
Please disable the adBlock and continue. Thank you.