Question

If a:b=2:3 and b:c=4:5, find a:b:c.

Give me the solution by explaining and give me a picture​

Answer 1

Answer:=9:12:15:17

Step-by-step explanation: There are two ways of solving this question.

firstly,

given A:B=3:4

B:C=8:10

C:D=15:17

now, we ll find A,B,C,D respectively and then calculate the ratio

A=3x8x15 =360

now for calculating B we ll take B’s share in A:B i.e. 4 instead of 3 and rest remains the same

B=4*8*15=480

similarly for c

C=4*10*15=600

and similarly in D’s share we ll take 4,10&17

D=4*10*17=680

so A:B:C:D=9:12:15:17 (dividing all by 4)

thats the answer …this is simple ratio and proportion logic and will help in each variety of these questions.

second way is a short cut way and it’ll save a lot of time.

we have

A:B=3:4

B:C=8:10

C:D=15:17

now , we know in A:B ….A’s share is a multiple of 3 (generally written 3k)

say A=3k so, B’s share will be 4/3 of A’s share …i.e. B=4k

similarly C’s share will be 10/8 of B’s share…i.e. C=5k

and D’s share will be 17/15 of C’s share(5k) i.e…D=17/3k

multilplying complete by 3 we will get A=9k ;B=12k ;C=15k ;D=17k

so ratio A:B:C:D=9:12:15:17