Given:
The initial selling price of cooker = Rs.620
The final selling price of cooker = Rs.580
His loss increased by = 4%
Formula used:
Loss = cost price (CP) – selling price (SP)
Loss % = (loss/CP) × 100
Calculation:
Let the CP of the cooker be Rs.x
The initial selling price of cooker = Rs.620
So, his initial loss = Rs. (x – 620)
Loss % = [(x – 620)/x] × 100
The final selling price of cooker = Rs.580
Then his final loss = Rs. (x – 580)
Loss % = [(x – 580)/x] × 100
Now by the question, his loss percent increases by 4%
⇒ [(x – 580)/x] × 100 = [{(x – 620)/x} × 100] + 4
⇒ 100x – 58,000 = 100x – 62000 + 4x
⇒ 104x – 100x = 62000 – 58000
⇒ 4x = 4000
⇒ x = 1000
∴ The cost price of the cooker is Rs. 1000
Alternate Method
4% → 620 - 580 = 40
1% → 10
100% → 1000
∴ The cost price of the cooker is Rs. 1000