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Look at this riddle? If she answers the riddle correctly how ever will she pay for the pencils?

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Question

Look at this riddle?
If she answers the riddle correctly how ever will she pay for the pencils?

Sum
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Solution

Let, the cost of one pencil be ₹ x.

Now, the cost of such 7 pencils will be ₹ 7x and of 5 pencils will be ₹ 5x.

It is given that cost of 7 pencils is ₹ 6 more than the cost of 5 pencils.

Therefore, we get the following equation

7x – 5x = 6

⇒ 2x = 6

⇒ `(2x)/2 = 6/2`  ...[Dividing both sides by 2]

⇒ x = 3

Since, the cost of one pencil is ₹ 3.

So, the cost of 10 pencils = 3 × 10 = ₹ 30

Thus, she has to pay ₹ 30 for 10 pencils.

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Chapter 4: Simple Equations - Exercise [Page 114]

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NCERT Exemplar Mathematics Exemplar Class 7
Chapter 4 Simple Equations
Exercise | Q 100. | Page 114

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