Answer:
19/2 or 9.5
Step-by-step explanation:
Step 1: Simplify both sides of the equation.
4(x−5)(2)=36
8x+−40=36(Distribute)
8x−40=36
Step 2: Add 40 to both sides.
8x−40+40=36+40
8x=76
Step 3: Divide both sides by 8.
8x/8=76/8
x=19/2
Let x be the unknown number. The equation is going to be 7/28=25/x, now we cross multiply. 7*x=25*28, 7x=700, divide both sides by 7 and you should get 100, So, x=100 and 7/28=25/100
Answer:
r = 1/3
= 1
Step-by-step explanation:
1 + 1/3 + 1/9 + 1/27 + 1/ 81
In this series a is the first term = 1
r is the common ratio = 2nd term/1st term = 3rd term/ 2nd term
r = 1/3 ÷ 1 = 1/9 ÷ 1/3
r = 1/3
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Answer:
B. 95% confident the average concentration of PCBs in the water supply is between 2.9 ppb and 3.5 ppb
Step-by-step explanation:
You are given the total number of samples, the concentration of lead, and the standard deviation. The standard deviation represents how inaccurate the estimation of the concentration of lead in the drinking water. This means that there can only possibly be a 0.3 ppb error in the estimation. 3.2-0.3=2.9, and 3.2+0.3=3.5
