tentang perbandingan 40:(x+3)=5:2

40/(x+3) = 5/2
(x+3).5 = 40.2
5x +15 = 80
5x = 65
x = 13

a      : b
40    : (x+3)
5      : 2
kali silang
40x2 =(x+3) x 5
80 = 5x + 15
80-15 = 5x
65/5 =x
x= 13
maka (x+3) => 13+3 =16
40 : 16 = 5: 2