Profit and loss 36 - 10th grade

Mr. Will Made a loss of 15% calculated on the selling price;
what will be the loss percent on the cost price?

Solution: Let the selling price = $100

So, loss = ${100 * (115/100)} = $15

So, the cost price = $(100 + 15) = $115

On $115 loss is $15

So, on $1 loss is $(15/115)

So, on $100 los is ${(15/115) * 100} = $(300/23)

= $13 ¹/₂₃

So, the required rate of loss = 13 ¹/₂₃ %