Question

The c.p. of two watchestaken together is R's840.if by selling one at a profit of 16% and the other at a loss of 12% , there is no gain or loss in the whole transaction than find the c.p. of each watch.

Answer 1

x= cost of 1 watch
y= cost of second watch

1.00 x + 1.00 y = 840.00 .............1
Total value
0.16 x -0.12 y = 0.00 .............2
Eliminate y
multiply (1)by 0.12
Multiply (2) by 1.00
0.12 x 0.12 y = 100.80
0.16 x -0.12 y = 0.00
Add the two equations
0.28 x = 100.80
/ 0.28
x = 360.00
plug value of x in (1)
1.00 x + 1.00 y = 840.00
360.00 + y = 840.00
y = 840.00 -360.00
y = 480.00
y = 480.00
x= 360.00 cost of 1 watch 0.00
y= 480.00 cost of second watch 0.00