4. (a) 8/14 = 4/7
20/35 = 4/7
(b) 6/10 = 3/5
15/25 = 3/5
(c) 9/4
36/16 = 9/4
(d) 12/15 = 4/5
30/40 = 3/4
The answer is D.
5. 8/18 = n/45
18 x n = 45 x 8
18 x n = 360
n = 360/18
= 20
The answer is C.
6. 0.6/1.6 = w/1.2
0.6 x 1.2 = w x 1.6
0.72 = w x 1.6
0.72/1.6 = w
w = 0.45
The answer is A.