Answer:
The speed of the boat is 20 km/hr
Step-by-step explanation:
Let s be the speed of boat in still water
Let d be the distance
Upstream speed = s-4
Jane took 30 min to drive her boat upstream to water-ski at her favorite spot.
So, Distance traveled in upstream =
Downstream speed = s+4
So, Distance traveled in downstream = 
So, 
30s-120=20s+80
10s=200
s=20
Hence The speed of the boat is 20 km/hr
Answer:
Step-by-step explanation:
plug y into the first equation:
8x+5y=24
8x+5(-4x)=24
8x-20x=24
-12x=24
x=-24/12
x=-2
then plug x to the second equation
y=-4
y=-4(-2)
y=8
x=-2
y=8
100 < 50(1.12)t
2 < (1.12)t
ln 2 < t ln (1.12)
0.6931 < t(0.1133)
6.117 < t
Answer:
b = 22 m
Step-by-step explanation:
The formula for calculating the area (A) of a triangle is
A =
bh
multiply both sides by 2 to eliminate the fraction
2A = bh ( divide both sides by h )
b =
, hence
b =
=
= 22 m
Answer:
8-7r
Step-by-step explanation: