The cost of 5 pens and 8 pencils is Z 120, while the cost of 8 pens and 5 pencils is Z 153. Find the cost of 1 pen and that of 1 pencil.
Let us assume the cost of 1 pen is Rs x and that of pencil is Rs y
According to the question, we have
5x + 8y = 120 …(i)
8x + 5y = 153 …(ii)
Now, adding both the equations we get:
13x + 13y = 273
13 (x + y) = 273
x + y = 21 …(iii)
Now, by subtracting (i) from (ii) we get:
3x – 3y = 33
x – y = 11 …(iv)
By adding (iii) and (iv), we get:
2x = 32
Putting the value of x in (iii), we get
16 + y = 21
y = 21 – 16
y = 5
∴ The cost of 1 pen is Rs. 16 and that of 1 pencil is Rs. 5