Question

A man buys 5 watches and 9 clocks for Rs. 15,500, if he
sells the watches at 12% profit and the clocks at 15%
profit, then he earns a total profit of Rs.1950. The
cost of a watch is:​

Answer 1

Answer:

Rs. 2500.00

Step-by-step explanation:

Let "w" be cost of the watch and "c" is cost of the clock, then

5w + 9c = 15500

0.12(5w) + 0.15(9c) = 1950 ⇔ 0.6w + 1.35c = 1950

5w + 9c = 15500

0.6w + 1.35c = 1950

$A = \left[\begin{array}{cc}5&9&\\0.6&1.35&\end{array}\right] = \frac{20}{27}$

$A_{w}= \left[\begin{array}{cc}15500&9&\\1950&1.35&\\\end{array}\right] =3375$

$w = \frac{A_{w}}{A} = 3375/ \frac{27}{20} = \frac{3375*20}{27} = 2500$

Cost of watch is Rs. 2500.00