Ni : Zn: Cu = 7:2:9 =7x : 2x : 9x
7x+2x+9x = 3.8
18x=3.8
x=3.8/18=1.9/9≈0.21
Ni: 7x=7*0.21=1.47 ≈1.5 kg
Zn: 2x=2*0.21=0.42≈0.4 kg
Cu: 9x=9*0.21=1.89 ≈1.9 kg
Check 1.5+0.4+1.9 =3.8 True
Answer:
FV(n)=42,000(1.04)^n
Step-by-step explanation:
FV=PV(1+r/n)^nt
Where
FV=future value
PV=present value
r=interest rate
n=number of periods
t=time (years)
PV=42,000
r=4%=0.04
n=1
t=n
FV(n)=p(1+r/n)^nt
=42,000(1+0.04/1)^1*n
=420000(1+0.04)^n
=42,000(1.04)^n
FV(n)=42,000(1.04)^n
Triangles ABC and DEF may or may not be congruent, because the angle-angle-angle (AAA) postulate is not a criterion for congruency of any two triangles. This is because the angle-angle-angle postulate only incorporates the angles of the triangles, and the side lengths are not specified, so congruency may or may not be true for these triangles.
Answer: The value of x must be greater than 3
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Explanation:
The triangle inequality theorem will come into play here. The basic idea of this theorem is "take any two sides of a triangle and add them up. That sum must be larger than the third side".
So if we have
a = 12
b = x
c = 15
then the following must hold true (all three inequalities must be true)
a+b > c
a+c > b
b+c > a
Focus on the first inequality and plug in the given values. Then solve for x
a+b > c
12+x > 15
12+x-12 > 15-12
x > 3
So we see that x > 3. Repeat the same for the second inequality
a+c > b
12+15 > x
27 > x
x < 27
Repeat again for the third inequality
b+c > a
x+15 > 12
x+15-15 > 12-15
x > -3
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In summary so far, we have
x > 3
x < 27
x > -3
Combine all of those inequalities to form one single compound inequality which is 3 < x < 27
For some reason your teacher doesn't want you to focus on the "less than 27" part, so it seems like s/he only wants the "x > 3" portion.
So this is why x must be larger than 3 (up only til you get to 27 though).
