Question

plzz tell me the final answer

Answer 1

Hello,
let the first pipe takes n minutes to fill the tank.
the time taken by second pipe to fill the tanks is:
n+5 minutes

let the volume of the thank be V.
the volume of the tank filled by the first pipe in 1 minutes is:
V₁=V/n
the volume of the tank filled by the second pipe in 1 minutes is:
V₂=V/n+5
the volume of the tank filled by boty in 1 minutes is:
V=V₁+V₂=V/n+V/n+5

give, time taken by two piper to fill the tank is 6 minutes.
the volume of the tank filled by boty in 1 minutes is:
V=6(V/n+V/n+5);
so:
6(n+5+n)/n(n+5)=1;
6(2n+5)/n(n+5)=1×n(n+5);
12n+30=n²+5n;
n²-7n-30=0;
n²-10x+3n-30=0;
n(n-10)+3(n-10)=0;
(x-10)(n+3)=0;
n-10=0 or n+3=0;
n=10 or n=-3
time cannot to be negative,then:
n=10 

thus,
the time taken by first pipe of fill the tank is= 10 minutes;
the time taken by secod pipe of fill the tank is
n+5=(10+5)= 15 minutes

bye :-)