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.
In the case of first tape-recorder :
S.P.= Rs. 990
Gain = 10%
C.P. =100(100+gain×S.P.
= 100(100+10)×Rs.990=Rs.100110×990
=Rs. 100×9=Rs.900
In the case of second tape-recorder:
S.P. = Rs. 990
Loss = 10%
C.P. = 100(100−10)×Rs.990=10090×990
= 100×11=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