Question

Question 100

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

Answer 1

Let, the cost of one pencil be Rs. x.
Now, cost of such 7 pencils will be Rs. 7x and that of 5 pencils will be Rs. 5x.
It is given that cost of 7 pencils is Rs. 6 more than cost of 5 pencils. Therefore, we get the following equation
7x - 5x = 6
$\Rightarrow 2x=6\Rightarrow \frac{2x}{2}=\frac{6}{2}\Rightarrow x=3$
Since, cost of one pencil is Rs. 3.
So, the cost of 10 pencils = $3\times 10=Rs.30$
Thus, she have to pay Rs. 30 for 10 pencils.