17. A man can row at 8 km/hr in still water. If the river is running at 2 km/hr, it takes him 48
minutes to row to a place and coming back. How
far is the place ?
(a) 1 km
(b) 2 km en
(c) 3 km
(d) 4 km

(c) 3 km

Step-by-step explanation:

Speed in still water: 8 km/h

Speed of river: 2 km/h

Speed downstream: 8 km/h + 2 km/y = 10 km/h

Speed upstream: 8 km/h - 2 km/h = 6 km/h

total time both ways: 48 minutes = 48/60 hour = 0.8 hour

time to go upstream: t

time to go downstream: 0.8 - t

speed = distance/time

s = d/t

d = st

Upstream:

d =  st

d = 6t

Downstream:

d = st

d = 10(0.8 - t)

The distance upstream and downstream is the same.

6t = 10(0.8 - t)

6t = 8 - 10t

16t = 8

t = 0.5

d = 6t = 6(0.5)

d = 3

(c) 3 km

step-by-step explanation:

10.50 + taxes which added up to 11.50

x=-2

infinite number of lines, so there is an infinite number of equations.

step-by-step explanation:

there are an infinite number of line that passes through the point (-2,5)

x=-2   is one line that passes through the point

y = 5 is another line that passes through the point

(these two lines are perpendicular to each other).

since the number of   numbers are infinite and the slope is the ratio of two numbers,(change in y over change in x) we can have an infinite number of slopes.     our only condition is that it passes through the point (-2,5)