Question

by selling a watch for rs.620 a man loses 7%. find the profit or loss percent when he sells the same for rs 700

Answer 1

Let cost price = Rs. x
selling price = Rs. 620
loss = 7%

$\frac{x-620}{x}*100=7$

⇒$\frac{x-620}{x} = \frac{7}{100} = 0.07$

⇒$x - 620 = 0.07x$
⇒$x -0.07x = 620$
⇒$0.93x = 620$

⇒$x = \frac{620}{0.93} = \frac{62000}{93}= 666.67$

Now selling price = 700

Profit = $\frac{700- 666.67 }{ 666.67 } *100 =$ = 4.99% ≈5%

Answer 2

At 620 loss of 7% is suffered 
so 0.93 of cp=620
⇒cp=666.67
if sold for 700 
profit=33.33
profit%=(33.33/666.67)*100
          =4.99%≈5%