Question

find the cost of 4 by 7 kg sugar at rupees 42 per kg ​

Answer 1

Answer:

Let’s assume the cost of 1 kg of sugar = Rs x

And, let the cost of 1 kg of rice = Rs y

Then according to the given conditions, we have

5x+7y=153      … (i) and

7x+5y=147      … (ii)

Multiplying (i) by 7 and (ii) by 5, we have

35x+49y=1071 … (iii)

35x+25y=735 … (iv)

Subtracting (iv) from (iii), we get

24y=336

⇒y=336/24

⇒y=14

On substituting the value of y in (i), we get

5x+7(14)=153

⇒5x+98=153

⇒5x=153−98

⇒5x=55

⇒x=55/5=11

Hence,

The cost of 1 kg of sugar is Rs 11 and 

The cost of 1 kg of rice is Rs 14.

Now,

Cost of 6 kg of sugar = Rs 11×6= Rs 66

Cost of 10 kg of rice = Rs 14×10= Rs 140

Thus, the cost of 6 kg of sugar and 10 kg of rice = Rs 66+ Rs 140= Rs 206.

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