Aptitude - Ratio and Proportion - Discussion

How come 24/5?

Thanks @Kalpa.

Given A:B = 2:3 and B:C = 5:8.

Our objective is to make the ratio of B same in both the given ratios so we multiply 5 with A:B and 3 with B:C.

B becomes 15 and we get the original ratio i.e., 10:15:24.

Thanks @Kalpa.

let the 3 numbers be x,y,z.

Given is x:y = 2:3 and y:z = 5:8.

So from here we see that y is the common term in both the ratio.

When we will do now is make the value of "y" same in both the ratio.
so in the first ratio, we will multiply the x:y with 5 and the new ratio of x:y will become x:y = 10:15.

And similarly, in the second ratio, we will multiply the y:z with 3 and the new ratio of y:z will become y:z = 15:24
now from the above two newly formed ratio we see that the value of y is the same that is 15.

So from here, we can write the final ratio or proportion of x:y:z as 10:15:24.

So according to the given question, the sum of ratios of x,y,z is 98.

Threrefore, we can write: 10n + 15n + 24n = 98.
=> 49n =98,
=> n = 2,
Thus value of y(the second term) is = 15 n = 15 * 2 = 30.

2:3. 2*5=10. 5*3=15. 3*8=24
5:8. 15/49*98=30.
It is easy for time saving the exam.

A:B =2:3.
B:C = 5:8.
A:B:C = 10:15:24.

Therefore,
A=98*10/49;
B=98*15/49;
C=98*24/49;

Hence the result is easy.

x:y:z
2:3:3 ~1
5:5:8 ~2
Then multiply 1 and 2 we get 10:15:24.

10+15+24 = 98.
49 = 98.
1 = 2.
15x2 = 30.

2:3
--5:8
_______
10:15:24
________
Now total sum is 98.
Then 10+15+24=49.
(98*15/49)=(2*15)=30.

@All.

Solution:

A: B = 2:3 and B: C = 5:8.
So Multiply A: B by 5 and B: C by 3.
So, we got a common B.

A: B = 10:15 and B: C = 15:24.

Total sum = 10+15+24 = 49,
Now, we want B so we simply.
B = (15/49)*Sum of total numbers (GIVEN).

B = (15/49)*98.
we get 30.