Three rods of equal length and equal area of cross section are connected end to end in series. The open end of the first rod (from left) is at a temperature of `300^@C` and that of the last rod is at `20^@C` in steady state. If the thermal conductivities of rods from left to right are in the ratio of 1: 3: 4, then find the temperatures of both the junctions.

Explanation

To solve the problem of finding the temperatures at the junctions of three rods connected in series, we can follow these steps:

### Step 1: Understand the Setup
We have three rods connected in series, with the following conditions:
- The temperature at the left end of the first rod is \( T_0 = 300^\circ C \).
- The temperature at the right end of the last rod is \( T_3 = 20^\circ C \).
- The thermal conductivities of the rods are in the ratio \( 1:3:4 \).

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