Question

Mr. Sinha sold two tape-recorders for Rs.990 each; gaining 10% on one and losing 10% on the other. Find his total loss or gain, as percent, on the whole transaction.

Answer 1

In the case of first tape-recorder :
S.P.= Rs. 990
Gain = 10%
C.P. =$\frac{100}{(100+gain}\times S.P.$
= $\frac{100}{(100+10)}\times Rs.990=Rs.\frac{100}{110}\times 990$
=Rs. $100\times 9=Rs.900$
In the case of second tape-recorder:
S.P. = Rs. 990
Loss = 10%
C.P. = $\frac{100}{(100-10)}\times Rs.990=\frac{100}{90}\times 990$
= $100\times 11=Rs.1100$
Total C.P. of both the tape recorders
=Rs. 900+Rs. 1100 = Rs. 2000
Total S.P. of both the tape recorders
=Rs. 990+ Rs. 990 =Rs. 1980
Loss on the whole transaction
= C.P. - S.P. = Rs. 2000- Rs.1980
= Rs. 20