HOW TO FIND COST PRICE

Cost price when there is a profit

Cost price when there is a loss

Example 1 :

A man sells two wrist watches at $ 594 each. On one he gains 10% and on the other he loses 10%. Find his gain or loss percent on the whole.

Solution :

Selling price of the first wrist watch = $ 594 and

gain% = 10%

Cost price of the first wrist watch

  =  [ 100/(100 + profit %) ] ⋅ Selling price

  =  [ 100 / (100 + 10) ] ⋅ 594

  =  (100 / 110) ⋅ 594

  =  $540

Similarly, C.P. of the second watch on which he loses 10% is

  =  [ 100/(100 - loss %) ] ⋅ Selling price

  =  [ 100 / (100 - 10) ] ⋅ 594

  =  (100 / 90) ⋅ 594

  =  $660

To say whether there was an overall Profit or Loss, we need to find the combined cost price and selling price.

Total cost price of the two watches = 540 + 660 = 1200.

Total selling price of the two watches = 594 + 594 = 1188.

Net Loss = 1200 – 1188 = 12

Loss %  =  ( Loss / Cost price ) ⋅ 100

  =  (12/1200) ⋅ 100

=  1 %

Example 2 :

By selling a table for $1,320, a trader gains 10%. Find the cost price of the table.

Solution :

Selling price  =  $ 1320

Profit %  =  10%

Cost price   =  [ 100/(100 + profit %) ] ⋅ Selling price

  =  [ 100/(100 + 10) ] ⋅ 1320

=  (100/110) ⋅ 1320

=  %1200

Example 3 :

A man sold two vehicles of his dog for $3605 each. On one he made a gain of 15% and on the other a loss of 9%. Find his overall gain or loss. 

Solution :

Selling price of the first vehicle = $3605  and

gain% = 15%

Cost price of the first vehicle

  =  [ 100/(100 + profit %) ] ⋅ Selling price

  =  [ 100 / (100 + 15) ] ⋅ 3605

  =  (100 / 115) ⋅ 3605

  =  $3134

Similarly, C.P. of the second watch on which he loses 9% is

  =  [ 100/(100 - loss %) ] ⋅ Selling price

  =  [ 100 / (100 - 9) ] ⋅ 3605

  =  (100 / 91) ⋅ 3605

  =  $3961

To say whether there was an overall Profit or Loss, we need to find the combined cost price and selling price.

Total cost price of the two watches

= 3134 + 3961

= 7095

Total selling price of the two watches

= 3605 + 3605

= 7210

Selling price > Cost price

Profit = 7210 - 7095 = 115

Related topics

• How to find cost price
• How to find selling price
• How to find percent of discount

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