If 5A - 2B = 0 and 4B - 5C = 0, then C : A = ? 

Correct option is B

Given:

​$$5A−2B=0$$ .....(Eq1)

$$4B−5C=0$$ .........(Eq2)

Ratio C : A = ?

Solution:

From equation (1):

​$$2B = 5A$$ 

$$B = \frac{5A}{2}$$ 

From equation (2):

​$$5C = 4B$$ 

​$$C = \frac{4B}{5}$$ 

Now, substitute $$B = \frac{5A}{2}$$​ into the equation for $C$

$$C= \frac{4}{5} \times \frac{5A}{2}$$​  

​$$C = \frac{20A}{10}$$ 

$$C= 2A$$ 

$$\frac{C}{A} = \frac{2}{1}$$ 

Thus C : A = 2 : 1