Question

if a:b=1:2,b:c=9:15,c:d=20:18 find a:b:c:d

Answer 1

first of all finda:b:c
1:2
9:15
now multiply 1*9:2*9
2*9:2*15
=>> 9:18
18:30
so 18 is common a:b:c=9:18:30
now 9:18:30
20:18
20*9:20*18:20*30
30*20:30*18
180:360:600
600:540
a:b:c:d= 180:360:600:540
hope it helps. If it helps mark it brainliest

Answer 2

Hi ,

i ) a/b = 1/2

a = b/2 ----( 1 )

ii ) b/c = 9/15 = 3/5

c/b = 5/3

c = 5b/3 ------( 2 )

iii ) c/d = 20/18 = 10/9

d/c = 9/10

d = 9c/10

d = ( 9/10 ) ( 5b/3 ) [ from ( 2 ) ]

d = 3b/2 ---( 3 )

Now ,

a : b : c : d

= b/2 : b : 5b/3 : 3b/2

= 1/2 : 1 : 5/3 : 3/2

= 3/6 : 6/6 : 10/6 : 9/6

= 3 : 6 : 10 : 9

Therefore ,

a : b : c : d = 3 : 6 : 10 : 9

I hope this helps you.

: )