Aboat travels 12 km upstream and back in 1 hour 45 minutes. if the speed of the current is 3 km/h throughout, find the speed of the boat in still water, giving your answer correct to 3 significant figures.

14.3 km/h   to 3 significant figures

Step-by-step explanation:

Let time travelling upstream be t1 hours and downstream = t2 hours.

t1 + t2 = 1.75(1)

Let v  be the speed of the boat in still water.

12 / t1 = v - 3(2)

12 /  t2 = v + 3(3)

From (1) and (3) , substituting for t2:-

12 / (1.75 - t1) = v + 3 (4)

Subtract:-   (2) - (4):-

12 / t1 - 12 / (1.75 - t1) = -6

12(1 .75 - t1) - 12t1 = -6t1(1.75 -  t1)

21 - 12t1 - 12t1 = -10.5t1 + 6t^2

6t1^2 + 13.5t1 - 21 = 0

Solving this gives t1 = 1.058 hours

Therefore the speed in still water (v)  = 12/1.058 + 3 = 14.3 to 3 sig figs

the most boring thing ever written

step-by-step explanation:

i am writing something. yes, i plan to make it the most boring thing ever written. i go to the store. a car is parked. many cars are parked or moving. some are blue. some are tan. they have windows. in the store, there are items for sale. these include such things as soap, detergent, magazines, and lettuce. you can enhance your life with these products. soap can be used for bathing, be it in a bathtub or in a shower. apply the soap to your body and rinse. detergent is used to wash clothes. place your dirty clothes into a washing machine and add some detergent as directed on the box. select the appropriate settings on your washing machine and you should be ready to begin. magazines are stapled reading material made with glossy paper, and they cover a wide variety of topics, ranging from news and politics to business and stock market information. some magazines are concerned with more recreational topics, like sports card collecting or different kinds of hairstyles. lettuce is a vegetable.