On selling a table for Rs. 210 and Rs. 420 there will be loss of L₁ % and L₂ % respectively. If L₁ - L₂ = 7, then what is the cost price of table.

Rs. 3,000

We have,

First selling price of a table = Rs. 210

Another selling price of a table = Rs. 420

There will be loss of L1% and L2 % respectively.

L1 - L2 = 7

According to the question,

SP₁ = Rs. 210

= CP = 100 × 210/(100 - L₁%) 

= SP₂ = Rs. 420

= CP = 100 × 420/(100 - L₂%) 

We know that, both CP are equal, 

= 100 × 210/(100 - L1%) = 100 × 420/(100 - L2%) 

= 210/(100 - L1%) = 420/(100 - L2%)

= 2(100 - L1%) = (100 - L2%)

= 200 - 2L₁ = 100 - L₂

= 2L₁ - L₂ = 100

Given, L1 - L2 = 7. 

= L₁ = 7 + L₂

Put the value of L₁

= 2(7 + L₂) - L2 = 100

= 14 + 2L₂ - L₂ = 100

= L₂ = 86%

= CP = 100 × 420/(100 - 86) 

= CP = 100 × 420/14

= CP = 100 × 30 = 3000