Mathematics
A lady has 25-P and 50-P coins in her purse. If in all she has 80 coins totalling ₹ 25, how many coins of each kind does she have ?
Linear Equations
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Answer
Let Number of 25-P coins be x and number of 50-P coins be y.
Given,
Total number of coins = 80,
⇒ x + y = 80
⇒ x = 80 - y ………(1)
Given,
Total value = ₹ 25 = 2500 paise,
⇒ 25x + 50y = 2500 …….(2)
Substituting value of x from equation (1) in 25x + 50y = 2500, we get :
⇒ 25x + 50y = 2500
⇒ 25(80 - y) + 50y = 2500
⇒ 2000 - 25y + 50y = 2500
⇒ -25y + 50y = 2500 - 2000
⇒ 25y = 500
⇒ y =
⇒ y = 20.
Substituting value of y in equation (1), we get :
⇒ x = 80 - y
⇒ x = 80 - 20
⇒ x = 60.
Hence, number of 25-P coins = 60 and number of 50-P coins = 20.
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