Question

A lady has some 10 paise coins and some 25 paise coins in her purse if in all she 60 coins totalling Rs. 8.25 how many coins of each denomination did she have?please explain each & every step

Answer 1

hola modi G,

let the number of 20 paisa coins be x and 25 paisa coins be y

so , 20x +25y = 1150 (1) ( convering values in paisa)

and x +y = 50 (2)

so x = 50 - y 

putting the value of x in equation (1)

so, 20(50 - y) + 25y = 1150

1000 - 20y + 25y = 1150

5y = 1150 -1000

5y = 150

y = 30

so the number of coins 25 paisa is 30 now putting this value of y in eq 2 

x + y = 50

x + 30= 50

and y =20

Answer 2

Let the number of 10 paise coins = x
and the number of 25 paise coins = y .

ATQ -->

x + y = 60 ...eqn(1)

and 10 x + 25 y = 8.25 * 100

10 x + 25 y = 825

5(2 x +5y ) = 5(165)

2x +5y =165 ....eq(2)

Multiplying first equation (1) by 2

2x + 2y =120 ...eq(3)

Subtracting equation 3 from 2

2x + 5y =165

2x +2y =120
===========
3y = 45

y = 15.

Substituting y value in equation 1

x + y = 60

x + 15 = 60

x = 45

Therefore ,Number of 10 paise , 25 paise coins with the lady are 45,15 respectively .