Question

A dealer of scientific instruments allows $20\%$ discount on the marked price of the instruments and still makes a profit of $25\%$. If his gain over the sale of an instrument is Rs. $150$, find the marked price of the instrument.

Answer 1

Let C.P of instrument $=Rs.100$
Profit $=25\%$ of $Rs.100=Rs.25$
If profit is $Rs.25,C.P=Rs.100$
$\therefore$ If profit is $Rs.150,$

$C.P=Rs.\frac{100}{25}\times 150=Rs.600$
S.P of the instrument $=Rs.600+Rs.150=Rs.750$
Let M.P of the instrument be Rs. 100
If S.P is Rs.80, $M.P=Rs.\frac{100}{80}\times 750=Rs.937.50$
Thus, marked price of the instrument $=Rs.937.50$