X + y = 40.....multiply by -4
4x + 6y = 180
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-4x - 4y = -160 (result of multiplying by -4)
4x + 6y = 180
------------------add
2y = 20
y = 20/2
y = 10 <===
x = 30
Answer:
4 I guess..........not sure but my answer is 4
Answer: 120
Step-by-step explanation:
From the question, we are informed that there are 10 people in a math club and that three people will be chosen for the Pi Day committee.
The number of different ways that the club members can structure the committee goes thus:
This can be solved by:
nCr = n! / r! (n - r)!
where n = 10
r = 3
= n! / r! (n - r)!
= 10! / 3! (10 - 3)!
= (10 × 9 × 8) / (3 × 2)
=120
Question a:
Mass = Density × Volume
Density = Mass/Volume
Volume of the tree trunk (the shape of Cylinder) = Area of circular base × height
Volume = [πr²] × h
Volume = [π × 0.25²] × 20
Volume = 3.93 m³
Density = 380 kg/m³
Mass = Density × Volume
Mass = 380 × 3.93
Mass = 1493.4 kg
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Question b)
The growth ring = 4 millimeters = 4÷1000 = 0.004
New diameter = 0.5 + 0.004 = 0.5004
New height = 20 + 0.2 = 20.2
New volume = [πr²] × h
New volume = [π × 0.2502²] × 20.2
New volume = 3.97 m³
