Answer:
one
Step-by-step explanation:
Speed of the boat = u
speed of the current = v
in downstream,
u - v = 105/5
u - v = 21
in upstream
u + v = 105/7
u + v = 15
add both equations
2u = 36
u = 18
v = -3
so
speed of the boat = 18 km/h
speed of the current = 3 km/h
Here are some examples of equations equal to 32.
16x2=32
64/2=32
9514 1404 393
Answer:
a) V = 4w²h
b) SA = 4w² +10wh
c) SA = 4w² +37.5/w
d) C = 40w² +225/w
Step-by-step explanation:
The relevant formulas are ...
V = LWH
base area = LW
lateral area = H(2(L+W))
__
a) The length is 4 times the width, so the volume is ...
V = (4w)(w)(h)
V = 4w²h
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b) The total surface area is the sum of the base area and the lateral area:
SA = base area + lateral area
SA = (4w)(w) + 2h(4w +w)
SA = 4w² +10wh
__
c) The volume is 15 m³, so the height in meters in terms of the width in meters is ...
15 = 4w²h
h = 15/(4w²)
Then the surface area is ...
SA = 4w² +10w(15/(4w²))
SA = 4w² +37.5/w
__
d) The equation we have for surface area has one term for base area and a second term for lateral area. We can apply the cost factors to those terms to get the cost of materials:
C = 10(4w²) +6(37.5/w)
C = 40w² +225/w
