Aptitude - Alligation or Mixture - Discussion

No its 2:3 only.
How it comes is that,

-> (6.30-7.20)=> -0.60.
-> (5.70-6.30)=> -0.90.

Upon equating them acc to allegations rule, you get,
0.2:0.3 which will be 2:3;

I guess it comes this way..am I right?

Let the ratio be x/1-x
Then
7.20 (1-x) + 5.70 x = 6.30
7.20 -7.20x + 5.70x =6.30
7.20-1.50x =6.30
7.20-6.30 /1.50 =x
0.90/1.50 = x
3/5 =x
1-x = 1-3/5 =2/5
x/1-x = 3/5 /2/5 = 3/2

According to books cheaper price shoul b taken firtt then dearer. So I think answer is 3:2. Please clear my doubt m I right?

worth of cost=6.30
so 6.30*100=630

den

720-630=90
630-570=60
so
90:30=2:3

How 630 came?

Rule of Alligation : If two ingredients are mixed, then :

c = Cost price of a unit quantity of cheaper

d= C.P. of a unit quantity of dearer



(Quantity of Cheaper) / (Quantity of dearer) = {(C.P. of Dearer) - (Mean price)} / {(Mean Price) - (C.P. of Cheaper)}


(Cheaper quantity) : (Dearer quantity) = (d - m) : (m - c)


c d
\ /
\/
/\mean price (m)
/ \
(d-m) (m-c)

Yes @Angeeta according me you are right.

I think it is a mistake.

It should be 90:60 or 3:2.

According to the formula the cheaper price is came frist and bearer price is second. so according to me the answer is 90:60=3:2
am i right?

@Ajay

630 - 570 = 60 and
720 - 630 = 90

It is simple.

How 60 & 90 came here?