An Envelope Contains 140 Pieces Consisting P1000 And, P500 Peso Bill If The Number Of P500 Is 20 More Than, The Number Of P1000 Peso Bill How Many P50

An envelope contains 140 pieces consisting P1000 and

P500 peso bill if the number of P500 IS 20 more than
the number of P1000 peso bill How many P500 peso bill
are there?
A 40
C. 80
B 70
D 60

 

Answer:

80

Step-by-step explanation:

x - number of P500 bill

y - number of P1000 bill

x + y = 140

x = y + 20

Solve y in terms of x using the second equation:

x = y + 20

- y = - x + 20

y = x - 20

Solve;

x + y = 140

x + (x - 20) = 140

2x - 20 = 140

2x = 160

x = 80