Question

Raju has certain notes of denominations 10 and 5 which amounts to 345. If the number of notes of each kind is interchanged, they amount to 45 less as before. Find the number of notes of each denominations​

Answer 1

Step-by-step explanation:

Let’s consider the number of 20 rupee notes to be x

And the number of 5 rupee notes be y

Then, according to the given conditions, we have

20x+5y=380     … (i) and

5x+20y=380−60

⇒5x+20y=320     … (ii)

Now, multiplying eq(i) by 4 and subtracting with eq(ii), we get

(80x+20y)−(5x+20y)=1520−320

⇒75x=1200

⇒x=751200

⇒x=16

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

20(16)+5y=380

⇒320+5y=380

⇒5y=380−320=60

⇒y=560

⇒y=12

Therefore, 

The number of 20 rupee notes =16 and 

The number of 5 rupee notes =12