Answer:
ksh 140
Step-by-step explanation:
When a watch is sold for ksh 126 a loss of x% is made, that is( 100 - x)%
Hence, the loss amount = (126 X 100)/(100 - x)
When the same watch is sold for ksh 154 a profit of x% is made, that is (100 + x)%
Hence, the profit amout = (154 X 100)/(100 + x)
Therefore, (126 X 100)/(100 - x) = (154 X 100)/(100 + x)
12600(100 + x) = 15400(100 - x)
1260000 + 12600x = 1540000 - 15400x
28000x = 280000
x = 10%
In that case for a watch sold for ksh 126 a loss 10% is made, that is( 100 - 10)%
Hence, loss amount = (126 X 100)/90 = ksh 140
∴ the buying price is ksh 140