Question

A bag contains 80 coins, which are either 50 paisa coins or 25 paisa coins. The total amount in the bag is Rs.25. How many coins in the bag are 25 paisa
coins?​

Answer 1

Answer:

Let there be x 50 paise coins and y number 25 paise coins

As there are total 50 coins. Accordingly

x + y = 50

x = 50 - y…Eq. 1

A total of 50 coins of 25 paise and 50 paise make a sum of Rs. 15.

0.50x + 0.25y = 15. Eq. 2

0.50 (50 - y) + 0.25y = 15

25 - 0.50y + 0.25y = 15

25 - 0.25y = 15

—0.25y = 15 - 25

—0.25y = —10

0.25y = 10

y = 10/0.25

y = 40

There are 40 nos. 25 paise coins

Substituting the value of y in Eq.1 to derive value of x

x = 50 - y

x = 50 - 40

x = 10

There are 10 nos. 50 paise coins

Answer 2

0.25n+0.5(80-n)=25

Solving the equatio,

We get n=60

So, number of 25 paisa coins is 60