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Amal buys 110 kg110 \mathrm{~kg} of syrup and 120 kg120 \mathrm{~kg} of juice, syrup being 20% less costly than juice, per kg. He sells 10 kg10 \mathrm{~kg} of syrup at 10% profit and 20 kg20 \mathrm{~kg} of juice at 20%20 \% profit. Mixing the remaining juice and syrup, Amal sells the mixture at Rs. 308.32308.32 per kg and makes an overall profit of 64%64 \%. Then, Amal's cost price for syrup, in rupees per kg, is

Entered answer:

Solution

✅ Correct Answer: 160

Since syrup is 20% less costly than juice, let's set up our variables:

Let cost price of juice = Rs 100x100x per kg

Then cost price of syrup = Rs 80x80x per kg

If juice costs Rs 100x100x, then 20% less would be Rs 100x−20x=80x100x - 20x = 80x

This clever choice of variables makes our calculations much easier.


Amal's purchases:

110 kg syrup at Rs 80x80x per kg = Rs 8800x8800x

120 kg juice at Rs 100x100x per kg = Rs 12000x12000x

Total Cost Price = Rs 8800x+12000x=20800x8800x + 12000x = 20800x


Individual sales:

10 kg syrup at 10% profit = 80x×1.1×10=880x80x \times 1.1 \times 10 = 880x

20 kg juice at 20% profit = 100x×1.2×20=2400x100x \times 1.2 \times 20 = 2400x

Mixed sales:

Remaining syrup = 110−10=100110 - 10 = 100 kg

Remaining juice = 120−20=100120 - 20 = 100 kg

Total mixture = 200 kg at Rs 308.32308.32 per kg = Rs 6166461664

Total Selling Price = Rs 880x+2400x+61664=3280x+61664880x + 2400x + 61664 = 3280x + 61664


Amal makes an overall profit of 64%.

This means: Selling Price = Cost Price ×1.64\times 1.64

So: Selling Price = 20800x×1.64=34112x20800x \times 1.64 = 34112x


Now we can equate our two expressions for selling price:

34112x=3280x+6166434112x = 3280x + 61664

30832x=6166430832x = 61664

x=6166430832=2x = \tfrac{61664}{30832} = 2


Cost price of syrup = 80x=80×2=16080x = 80 \times 2 = 160 per kg

We used smart variable choice (using 80x80x and 100x100x) to eliminate fraction calculations. We tracked quantities carefully by separating individual sales from mixed sales. We used overall profit percentage as a checking mechanism.

The answer is Rs 160 per kg.

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