Question

if a:b=9:10 and b:c=25:8 find a:b:c

a:b is =5:3 and b:c= 4:1 find a:b:c​

Answer 1

Answer:A:D=16:35

Step-by-step explanation:  If we have two proportions, and we want to make one (last element of first should be first element of second like a:b:c and c:d). We need to have last number of first and first number of second the same. We can take LCM as the common value.

A:B=2:3 and B:C=4:5

We should take LCM of 3 (Last element of first) and 4 (First element of second).

It is 12.

To bring 12 at that position, we inflate numbers is first proportion to bring 12 at last position (multiply all elements by 4) and second proportion by 3.

Now A:B=8:12 and B:C=12:15

We can see that proportion is maintained for both.

Now, we have got A:B:C=8:12:15 and C:D=6:7

LCM of 15 and 6 is 30. Multiplication by 2 and 5 the proportions respectively.

So, A:B:C=16:24:30 and C:D=30:35

Result is A:B:C:D=16:24:30:35

We can individually check back that A:B=16:24=2:3;B:C=24:30=4:5 and C:D=30:35=6:7.

From the result A:B:C:D=16:24:30:35 we can give relationship between any two.

A:D=16:35

Ans.:  A:D=16:35