Answer:
7 hamsters at 5 pesos each and 13 hamsters at 8 pesos each
Step-by-step explanation:
5x + 8y = 139
x + y = 20
x = 20 - y
5x + 8y = 139
5(20 - y) + 8y = 139
100 - 5y + 8y = 139
100 + 3y = 139
3y = 139 - 100
3y = 39
3y/3 = 39/3
y = 13
x + y = 20
x + 13 = 20
x = 20 - 13
x = 7
