Question

Sabendo que x/y= 1/2 e x+y=30. Calcule 2x+3y.
a) 80
b) 70
c) 60
d) 50
e) 40

Answer 1

x+y = 30
x = 30 - y

30 - y / y = 1/2
30 - y = y/2
30 = y/2 + y
30 = 3y/2
30 . 2 = 3y
60/3 = y
20 = y

x = 30 - y
x = 30 - 20
x = 10

2x + 3y
2(10) + 3(20)
20 + 60
80