Algebra
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Q.

Jay has with him a total of Rs 29 in 5-rupee and 2-rupee denominators. The number of 5-rupee notes in one-half of one less than the number of 2-rupee notes. How many 5-rupee notes and 2-rupee notes does Jay have respectively?

 A.

7,3

 B.

3,7

 C.

2,5

 D.

5,2

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Solution:
Option(B) is correct

Let $x$ be the 5-rupee notes and $y$ be the number of 2-rupee notes.

\(5x+2y=29\)-------- (i)

\(x=\dfrac{y-1}{2}\)

\(2x-y=-1\)-------- (ii)

On solving both the equation we get:

$x =\textbf{3}$ and $y =\textbf{7}$

Edit: For an alternative approach making use of the option choices, check comment by Sravan Reddy.


(1) Comment(s)


Sravan Reddy
 ()

Kill it in 10 sec:

=> Possible options: (3,7) and (2,5).

By calculating only 3,7 adds up to 29