Let’s assume the cost of an audio cassette and that of a video cassette be ₹ x and ₹ y, respectively.
Then forming equations according to the question, we have
7x + 3y = 1110 … (i)
5x + 4y = 1350 … (ii)
On multiplying equation (i) by 4 and equation (ii) by 3, We get,
28x + 12y = 4440 … (iii)
15x + 4y = 4050 … (iv)
Subtracting equation (iv) from equation (iii),
28x – 13x + 12y – 12y = 4440 – 4050
13x = 390
⇒ x = 30
On substituting x = 30 in equation (i)
7(30) + 3y = 1110
3y = 1110 – 210
y = 900/ 3
⇒ y = 300
Therefore, it’s found that the cost of one audio cassette = ₹ 30 And the cost of one video cassette = ₹ 300
