The correct option is A 4%
SP of each tape = ₹ 600
Total SP = 2 × 600 = ₹ 1200
Profit made on first tape = 20%
Let CP = ₹ 100
Then, Profit = 20% of 100 = ₹ 20
So, SP = 100 + 20 = ₹ 120
Thus, when SP is ₹ 120, CP is ₹ 100.
Now, if when SP is ₹ 1, then CP will be ₹ 100120.
∴ When SP is ₹ 600, CP is ₹ (100120×600).
⇒ CP = ₹ 500
Loss suffered on second tape = 20%
Let CP = ₹ 100
Then, Loss = 20% of 100 = ₹ 20
So, SP = 100 - 20 = ₹ 80
Thus, when SP is ₹ 80, CP is ₹ 100.
Now, if SP is ₹ 1, CP is ₹ 10080.
∴ When, SP is ₹ 600, CP is ₹ (10080×600).
⇒ CP = ₹ 750
So, total CP = 500 + 750 = ₹ 1250
Here, Net CP > Net SP
Loss = CP - SP
⇒ Loss = 1250 - 1200 = ₹ 50
Overall loss%=LossNet CP×100%
⇒Loss%=501250×100% =4%