Let's denote the cost of a pencil as 'p' and the cost of a pen as 'q'.

From the first statement, we can form the equation:
21p + 29q = 79

From the second statement, we can form the equation:
29p + 21q = 79 - 8 = 71

Now we have a system of two equations, and we can solve it step by step.

First, multiply the first equation by 29 and the second by 21, to make the coefficients of 'p' the same in both equations:

29*21p + 29*29q = 79*29
21*29p + 21*21q = 71*21

This gives us:

609p + 841q = 2291
609p + 441q = 1491

Now, subtract the second equation from the first:

609p + 841q - 609p - 441q = 2291 - 1491
400q = 800

Divide both sides by 400:

q = 800 / 400 = 2

So, each pen costs Rs. 2.

Question

Let's denote the cost of a pencil as 'p' and the cost of a pen as 'q'.

From the first statement, we can form the equation: 
21p + 29q = 79

From the second statement, we can form the equation: 
29p + 21q = 79 - 8 = 71

Now we have a system of two equations, and we can solve it step by step.

First, multiply the first equation by 29 and the second by 21, to make the coefficients of 'p' the same in both equations:

29*21p + 29*29q = 79*29
21*29p + 21*21q = 71*21

This gives us:

609p + 841q = 2291
609p + 441q = 1491

Now, subtract the second equation from the first:

609p + 841q - 609p - 441q = 2291 - 1491
400q = 800

Divide both sides by 400:

q = 800 / 400 = 2

So, each pen costs Rs. 2.

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