2 chocolates, 4 cakes and 3 milk shakes cost Rs.17. One chocolate and 2 cakes cost Rs.4. What is the cost of a milk shake?

To solve this problem, we can use the method of substitution from algebra.

Step 1: Let's denote the cost of one chocolate as 'c', one cake as 'k', and one milkshake as 'm'.

Step 2: From the problem, we can form two equations. The first equation from "2 chocolates, 4 cakes and 3 milk shakes cost Rs.17" is: 2c + 4k + 3m = 17

Step 3: The second equation from "One chocolate and 2 cakes cost Rs.4" is: c + 2k = 4

Step 4: We can rearrange the second equation to solve for 'c': c = 4 - 2k

Step 5: Now, we can substitute 'c' from the second equation into the first equation: 2(4 - 2k) + 4k + 3m = 17 8 - 4k + 4k + 3m = 17 8 + 3m = 17

Step 6: Solving for 'm', we get: 3m = 17 - 8 3m = 9 m = 9/3 m = 3

So, the cost of a milkshake is Rs.3.