Breakspace | Quants and LRDI doubts

R can come either 1st or last

Let salt qty in A,B and C are a,b,c resp.

Acc a+2b+3c=120 ...i

And 3a+2b+c=180...ii

ii-i we get a-c=30 or c=a-30 

putting c in i we get 2b=210-4a ..iii

Now strength of D=(2b+7c)/900

or D=(2b+7a-210)/900

Put eqn iii in above we get D=3a/900 and A=a/100

So D/A= 1:3

@sudarshanmandal https://imgur.com/p3BTEgO

2:24?

If the total distance is x then s(ashok)=x/t and s(biswas)=x/(144+t-66) = x/t+78 . Now ,they meet at 12.36 so x= x/t * 72 + x/(t+78) *216 . X gets cancelled calculate t you will get a quadratic equation on solving we get t equal to 179.something

@khan.moin00103 sir , yes the difference between two consecutive term is AP . But , why did we consider the general term an= x*n^2 + y*n +z ?

@anirbanjyotikar Whenever the difference is in AP, we can write general term in this form.

as now an= a + (n-1)d, where d is in AP, hence a linear equation in n.

so, d= bn+c

Now, we get, an= a+ (n-1)(bn+c) which is clearly a quadratic equation in 'n'