Question

70 coins of 10 paise and 50 paise are mixed in a purse. If the total money in the purse is Rs.19, find the no of each type of coin. ( plzz ans it fast )

Answer 1

Heya....
Here is your answer ---

Let the number of 10 paise coins be x
Then, the number of 50 paise coins = 70-x (since the total number of coin is 70)

ATQ

=> 10 (x) + 50 (70-x) = 1900 (Rs.19 in paise)
=> 10x + 3500 - 50x = 1900
=> -40x + 3500 = 1900
=> -40x = 1900 - 3500
=> -40x = -1600
=> x = -1600/ -40
=> x = 40

No. of 10 paise coins = x = 40
No. of 50 paise coins = 70-x = 70-40 = 30

CHECKING
(40×10) + (30×50) = 1900
400 + 1500 = 1900
1900 = 1900

HOPE IT HELPS....!!

Answer 2

you have 70 coins of 10 and 50 value, total value is 1900. 
I will call the 10 unit T, and 50 unit, F, in other words, T is the number of 10 units coins.
 
T+F=70
10T+50F=1900 
Now multiply first equation by -10 , both sides, 
-10T-10F=-700
10T+50F=1900 and add the second equation 
40F=1200 
F=30
T=40 
40*10 =400
30*50=1500 
Total value 1900