Answer:
7.8
Step-by-step explanation:
Sine 50=6/x
x= 6/Sine 50
x=7.8
We have 10 ml of 20% acid to which we need to add "x" milliliters of 100% acid to make 50% acid.
.20 * 10 + 1.00x = .50 * (10 +x)
in which "x" is the volume of the 100% acid to be added.
2 + x = 5 + .5 x
.5x = 3
x = 6 milliliters
Source:
http://www.1728.org/mixture.htm
Scroll down to problem B
Answer:
The ages of the four siblings are: 5, 7, 9 and 11 years old.
Step-by-step explanation:
The computation of the age of the four siblings is shown below:
Given that
n = 4
a1 =? a2 =? a3 =? a4 =?
a4 = a1 + 6 years
S4 = 32
Based on the above information
As we know that
Sn = (a1 + a4) × n ÷ 2
S4 = (a1 + a4) × 4 ÷ 2
32 = (a1 + a1 +6) × 2
16 = 2a1 + 6
2a1 = 10
a1 = 10 ÷ 2
= 5
So, a4 = a1 +6
= 5 +6
= 11
a4 = a1 + (4-1) × d
11 = 5 + 3 × d
d = 6 ÷ 3
= 2
So,
a2 = a1 + d
= 5 + 2
= 7
a3 = a2 + d
= 7 + 2
= 9
Hence, The ages of the four siblings are: 5, 7, 9 and 11 years old.
f(X)=3/x-1,g(x)=2/x
g.f(-5)=g(f(-5))=g(-3/5-1)=g(-3-5/5)=g(-8/5)=2×(-5/8)=-5/4
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