Answer:
Let speed of stream be x according to question, \[\frac{30}{x+15}+\frac{30}{15-x}=4+\frac{30}{60}\] \[30\frac{(15-x+x+15)}{{{(15)}^{2}}-{{(x)}^{2}}}=\frac{9}{2}\] \[\frac{900}{225-{{x}^{2}}}=\frac{9}{2}\] \[\Rightarrow \] \[\frac{2}{9}\times 900=225-{{x}^{2}}\] \[200=225-{{x}^{2}}\] or \[-{{x}^{2}}=200-225=-25\] or \[x=5\,\,km/hr.\] Speed of stream is \[=5\,\,km/hr.\]
You need to login to perform this action.
You will be redirected in
3 sec