Advertisements
Advertisements
प्रश्न
The speed of the boat in still water is 11 km/ hr. It can go 21 km upstream and 12 km downstream in 3 hours. Find the speed of the stream.
उत्तर
Let the speed of the stream be S km/ hr. So in upstream, boat speed will be 11-S (Against the water flow) and downstream will be S+ l 1 (Towards the water flow and hence speed is added).
Distance travelled = 21 Km Upstream and 12 km downstream
Total Time = 3 hours
Time = Distance / Speed.
`21/(11 - "S") + 12/(11 + "S") = 3`
⇒ 21(11+S) + 12 (11-S) = 3(11+S)(11-S)
⇒ 231 + 21S + 132 - 12S = -3S2 + 363
⇒ 3S2 + 9 s = 0
⇒ 3S(S+3)=0
⇒ S=O ,-3
S = O
Since, speed cannot be negative, thus, the speed of the stream is 0 km/ hr.
APPEARS IN
संबंधित प्रश्न
Solve `4/(x + 2) - 1/(x + 3) = 4/(2x + 1)`
Solve the following equation for x and give, in the following case, your answer correct to one decimal place:
5x2 + 10x – 3 = 0
Solve: x4 – 2x² – 3 = 0.
Solve the following equation using the formula:
`4/x - 3 = 5/(2x + 3)`
`x^2+6x+5=0`
`4x^2-2(a^2+b^2)x+a^2b^2=0`
`9x^2-9(a+b)x+(2a^2+5ab+2b^2)=0`
`a/(x-b)+b/(x-a)=2,x≠b,a`
Solve the following equation by using formula :
`(2)/(x + 2) - (1)/(x + 1) = (4)/(x + 4) - (3)/(x + 3)`
If the sum of the roots of a quadratic equation is 5 and the product of the roots is also 5, then the equation is:
