Question

A sum of rupees 500 is in the form of denomination of rupees 5 and rupees 10 . if the total number of the notes is 90 find the number of notes of each denomination

Answer 1

the possibility is 5*80 that is equal to 400 and 10*10 is 100.total notes would be 90

Answer 2

Answer:-

₹5 = 80

₹10 = 10

Solution :-

Let the number of notes of denomination 5 and rupees 10 be x and y.

A/Q

$x + y = 90$------eq1.

$5x + 10y = 500$

Dividing both side by 5 in eq. 2 ,

$\dfrac{5x}{5}+\dfrac{10y}{5}=\dfrac{500}{5}$

$\dfrac{\cancel{5}x }{\cancel{5}}+ \dfrac{\cancel{10}y}{\cancel{5}}=\dfrac{\cancel{500}}{\cancel{5}}$

$x + 2y = 100$----eq.2

Now, subtract this both eq. 1 and eq. 2 we get,

$x + y = 90\\x+2y = 100$

$x - x + y -2y = 90 - 100$

$-y = -10$

$\cancel{-}y = \cancel{-}10$

$y = 10$

Now put y= 10 in eq. 1

$x + 10 = 90 \\ x = 90-10 \\ x = 80$

hence, the number of notes of 5 is = 80 and number of notes of 10 be 10 .