Question

The speed of a boat in still water is 8km/hr. it can go 15 km upstream and 22 km downstream in 5 hours. find the speed of the stream.

Answer 1

Answer:

Step-by-step explanation:

let X be the speed of the stream

speed of the boat in still water = to 8 km /hr

thus the speed of the boat in upstream =(8-x) km/hr

speed of the boat in downstream =(8+x )km/hr

the time taken by boat to cover 15 km

the time taken by boat to cover 22 km

total time =5hrs (given)

x=3

since speed cannot be negative

Therefore speed of steam is 3km/hr

Answer 2

αηѕωєя

• ⇒ Let x be the speed of the stream.
• ⇒ Speed of the boat in still water is 8km/hr
• ⇒ The speed of the boat in upstream is 8−xkm/hr
• ⇒ The speed of the boat in downstream is 8+xkm/hr
• ⇒ The time taken by the boat to cover$15km= </li></ul><p>8−x</p><p>15</p><p> </p><p> hr$
  • ⇒ The time taken by the boat to cover$22km= </li></ul><p>8+x</p><p>22$
    • According to the question,

    ⇒

    $8−x</p><p>15</p><p> </p><p> + </p><p>8+x</p><p>22</p><p> </p><p> =5 \\ </p><p>⇒ 15(8+x)+22(8−x)=5(8−x)(8+x) \\ </p><p>⇒ 120+15x+176−22x=5(64−x </p><p>2</p><p> ) \\ </p><p>⇒ 296−7x=320−5x </p><p>2 \\ </p><p> </p><p>⇒ 5x </p><p>2</p><p> −7x−24=0</p><p>⇒ 5x </p><p>2</p><p>−15x+8x−24=0 \\ </p><p>⇒ 5x(x−3)+8(x−3)=0 \\ </p><p>⇒ (x−3)(5x+8)=0 \\ </p><p>⇒ x−3=0 and 5x+8=0 \\ </p><p>⇒ x=3 \: and \: x=− </p><p>5</p><p>8$

    • Speed cannot be negative.
    • ∴ The speed of the stream is 3km/hr

    $hope \: its \: help \: u$