7 audio cassettes and 3 video cassettes cost Rs 1110, while 5 audio cassettes and 4 video cassettes cost Rs 1350. Find the cost of an audio cassette and a video cassette.

Let the cost of an audio cassette be ‘a’ and a video cassette be ‘b’.


Given, 7 audio cassettes and 3 video cassettes cost Rs 1110.


7a + 3b = 1110 -------- (1)


Also, 5 audio cassettes and 4 video cassettes cost Rs 1350.


5a + 4b = 1350 -------- (2)


Multiplying eq1 by 4 and eq2 by 3 and subtracting eq2 from eq1.


28a + 12b – 15a – 12b = 4440 – 4050


13a = 390


a = Rs. 30


Substituting value of a in eq1


7 × 30 + 3b = 1110


3b = 900


b = Rs. 300


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