A man sells two watches for Rs 2100 and gains 5%. On the one watch he gains 7% while on the other he loses 3%. Find the CP of the watch on which he gains 7%

Can anyone explain, when solving the question via allegation method, why allegating profit/loss percent gives ratio of the cost price?

Question

A man sells two watches for Rs 2100 and gains 5%. On the one watch he gains 7% while on the other he loses 3%. Find the CP of the watch on which he gains 7%

Can anyone explain, when solving the question via allegation method, why allegating profit/loss percent gives ratio of the cost price?

Ayushman Talukder · Answer

Answer is Rs1600.
CP = 2100/1.05 = 2000 = x + y
also 1.07x+0.97y= 2100 solving we get y = 400 thus x = 2000-400 = 1600

Ayushman Talukder · Answer

Using alligations,

-3      7
    \ /
     5
   /   \
2      8

Thus 2/10 *2000 = 400(x) &amp; y = 8/10 *2000 = 1600(y). Because Profit%/Loss% is a subject to CP.

Kamal . · Answer

is it 1570

A man sells two watches for Rs 2100 and gains 5%. On the one watch he gains 7% while on the other he loses 3%. Find the CP of the watch on which he gains 7% Can anyone explain, when solving the question via allegation method, why allegating profit/loss percent gives ratio of the cost price?

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