Question

A man has only 20 paise coins and 25 paise coins in his purse. if he has 50 paise coins in all totaling rs 11.25, how many coins of each kind does he have?

Answer 1

let no. of 20 paise coins=x
no. of 25 paise coins=y
x+y=50
.20x+.25y=11.25
.20x+.25(50-x)=11.25
-.05x=11.25-12.50=-1.25
5x=125
x=25
no. of 20 paise coins=25
no. of 25 paise coins=25

Answer 2

Solution : Let number of 20 p coins be x and number of 25 p coins be y.

⇒ x + y = 50        .......(1)

Total cost of 20 p coins will be 20x because number of coins × their cost = total cost.

⇒ 20x + 25y = Rs 11.25

⇒ 20x + 25y = 1125 (paise) .....(2)

By multiplying 20 from eq(1),

⇒ 20x + 20y = 1000           ......(3)

By doing (2) - (3),

⇒ 5y = 125

⇒ y = 25

By substituting value of y we get,

⇒ x + 25 = 50

⇒ x = 25

Hence the man have same number of 20 p and 25 p coins.

Answer : 25 coins each