We would just double it, or multiply it by 2. .155 times 2 is set up just like regular multiplication. The answer is .310 as his batting average. Note: don't let the word "average" confuse you! Just look at the numbers in this case.
Let
x-->volume of white vinegar you need to add to the mixture (measured in cups)
<span>then
the amount of the pure vinegar in the mixture will be -----> (10*0.1 + x) cups
t</span>he volume of liquid will be ---------> 10 + x
the concentration equation is-------> [(10*0.1 + x)/(10+x)]=0.50<span>multiply both sides by (10+x) and then simplify
</span>(10*0.1 + x)=(10+x)*0.50-----------> 1+x=5+0.50x-------> 0.50x=4
x=8
the answer is
<span>you need to add 8 of a cup of the pure vinegar to the mixture</span>
Area of the figure:
Af = a² + 2 a²/4 π = 2.57 a²
Area of the shaded region:
As = 2 a²/4 π = 1.57 a²
x = (1.57 · 100) / 2.57 = 61 % ≈ 60 %
Answer: B) about 60 %