two dozens of apples cost rs 160.find the cost of 120 similar apples

1 dozen of apples = 12 apples
So two dozen of apples = $12\times 2$ = 24 apples
Cost of 2 dozen of apples = Rs.160
i.e. Cost of 24 apples = Rs. 160
Then, cost of 1 apple = $\frac{160}{24}$
So cost of 120 apples = $\frac{160}{24}\times 120$ = Rs.800
Therefore cost of 120 apples is Rs.800.