Question

Se știe că: a:b=3;b:2=c;a-b=40. Alfă: 3a-4b+5c.

Answer 1

a:b=3
a-b=40
a=3b
3b-b=40
2b=40
b=40:2
b=20
b:2=c
c=20:2=10
a=3b
a=20x3=60

3a-4b+5c=
3x60-4x20+5x10=
180-80+50=150

Answer 2

a : b = 3        a = 3b
b : 2 = c        b = 2c
a - b = 40
3b - b = 40
2b = 40
b = 20
a = 3 * 20
a = 60
c = b : 2
c = 20 : 2
c = 10
3 * 60 - 4 * 20 + 5 * 10 = 180 - 80 + 50 = 150