Question

21. A sells a watch to B at a gain of 10%. If
B pays 330 for it what is the cost price
for A?
1) 3320 2) * 340 3) * 300 4) 3310​

Answer 1

Answer:

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Step-by-step explanation:

First Method

Let Cost Price for A was 100

Then CP for B = 100 + 25% of 100 = 125

CP for C = 125 + 20% of 125 = 150

CP for D = 150 + 10% of 150 = 165

But, D pay Rs. 330, Then it must be equal to

165 = 330

1 = 330165

100 = 330×100165=200

Thus, CP for A = Rs. 200

Short-cut

A's CP = 330×100125×100120×100110

= Rs. 200