Answer:
The two solutions are
x
=
1
and
−
32
.
Step-by-step explanation:
<h3>
Answer: 14 km per hour</h3>
=====================================================
Work Shown:
x = rowing speed when there is no current
c = speed of the current
speeds are in km per hour
-----------
Going downstream, i.e. with the current:
x+c = faster speed since the current is pushing you
distance = rate*time
d = r*t
40 = (x+c)*2
x+c = 40/2
x+c = 20
c = 20-x
-----------
Going upstream, i.e. against the current:
x-c = slower speed since the current is working against you
d = r*t
16 = (x-c)*2
16 = 2x-2c
2x-2c = 16
2(x-c) = 16
x-c = 16/2
x-c = 8
x-(20-x) = 8 ... plug in c = 20-x
x-20+x = 8
2x-20 = 8
2x = 8+20
2x = 28
x = 28/2
x = 14 km per hour is the rowing speed when there is no current
Side note: the speed of the current is c = 20-x = 20-14 = 6 km per hour.
Answer: subtract
Step-by-step explanation:
look at it
1.7 hrs
Step-by-step explanation:
We can use cosine law to find the distance d:
where. a = 3 mi
b = 4 mi
gamma = 71.7°
d^2 = (3mi)^2 + (4 mi)^2 - 2(3 mi)(4 mi)cos(71.7)
= 9 mi^2 + 16 mi^2 -24cos(71.7)
= 17.464 mi^2
or
d = 4.2 mi
To find the time it takes for him to go from the cave to the waterfall, divide this distance d by his walking rate of 2.5 mi/hr:
t = d/v = 4.2 mi/2.5 mph
= 1.7 hrs
