Posts by Helga

Total # Posts: 29

  1. history

    Which laws called for strict separation of the races in the South? (1 point) anti-discrimination laws Plessy v. Ferguson laws Jim Crow laws ***** boycott laws 2. Civil rights activists targeted segregation in interstate transportation (1 point) because they knew that the ...
  2. maths

    The cost of a gift is shared amongst 3 kids. Keith paid €480 more than jack. Keith paid €220 more than the total amount paid by Jack and tim. Jack paid 80 more than tim. How much did the present cost?
  3. business studies

    can you please help me. issues that affect ethical and professional behaviour of the business
  4. Chemistry

    Can you put the figures into the equation for me, because I do not quite understand this?
  5. Chemistry

    One of the reactions that occurs in a blast furnace, in which iron ore is converted to cast iron, is Fe2O3 + 3CO → 2Fe + 3CO2 Suppose that 1.59 × 103 kg of Fe is obtained from a 2.54 × 103 kg sample of Fe2O3. Assuming that the reaction goes to completion, ...
  6. Math

    8 people are going to sit on 6 chairs. Two of them John and Kelly can't sit next to each other. How many ways can you put the people to seats? The answer is 10080, but I can't figure out how to calculate it.
  7. calculus

    Consider the function f(x)=x^n for positive integer values of n. (a) For what values of n does the function have a relative minimum at the origin? (b) For what values of n does the function have a point of inflection at the origin?
  8. Chemistry

    In the titration of 20.00 mL of 0.175 M NaOH, calculate the number of milliliters of 0.200 M HCl that must be added to reach a pH of 12,55. I know the answer is 11,9 mL but I don't know how to calculate it.
  9. research

    A quantitative analysis method which aggregates a number of (similar) individual studies into a large data set from which to compute an over all “effect size” (based on similar study procedures and treatments) is commonly known as…?
  10. Chemistry

    when 20 ml of a .10 M silver nitrate solution is mixed with 25 ml of a 0.080 M solution of sodium sulfide, producing a precipitate of silver sulfide, what is the final concentration of sulfide ion?
  11. Chemistry

    The oxides of Group 2A metals (symbolized by M here) react with carbon dioxide according to the following reaction: MO(s) + CO2(g)  MCO3(s) A 2.85-g sample containing only MgO and CuO is placed in a 3.00-L container. The container is filled with CO2 to a ...
  12. Chemistry

    A bicycle tire is filled with air to a pressure of 610 kPa at a temperature of 19 oC. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58 oC. The volume of the tire increases by 4.0%. What is the new pressure in the bicycle tire?
  13. Algebra

    Is there a more elegant solution than trial and error?
  14. Algebra

    How do I calculate 4^n=1/(2(n-n^2))? Thanks.
  15. Binomial expansion

    The coefficient of x^2 in the expansion of (4-3x)^n as a series of ascending powers of x is -9/64. Show that n satisfies the equation 4^(n+1)=2/[n(1-n)] and hence verify that n=1/2. I can do the first part of the problem: 4^n*3^2*n(n-1)/2!*2^4=-3^2/2^6 4*4^n*n(n-1)=-2 4^(n+1)*...
  16. Newton's Law of Cooling

    Oh, I see. So to make an estimate you'd have to make an assumption of ambient temperature, right? Assuming constant ambient temperature of 10°C, the time of death could be estimated to be at around 4.45 (i.e 4 to 4 1/2) hours before discovery. Is that correct?
  17. Newton's Law of Cooling

    Shame about your computer. Don't want to die wondering ;)
  18. Newton's Law of Cooling

    You are a forensic doctor called to a murder scene. When the victim was discovered, the body temperature was measured and found to be 20°C. You arrive one hour later and find the body temperature at that time to be 18°C. Assuming that the ambient temperature remained ...
  19. Calculus

    A container in the form of a right circular cone of height 16 cm and base radius 4 cm is held vertex downward and filled with liquid. If the liquid leaks out from the vertex at a rate of 4 cm^3/s, find the rate of change of the depth of the liquid in the cone when half of the ...
  20. Calculus

    A right circular cone has a constant volume. The height h and the base radius r can both vary. Find the rate at which h is changing with respect to r at the instant when r and h are equal.
  21. Pre-Calculus

    It may look lame but I can't work out how to solve (-9) sqrt(4-x^2) = 4x + 5sqrt2. I need some guidance, please.
  22. Calculus

    Differentiate x^2*y^2 = (y+1)/(x+1) in terms of x and y. PS My answer is unfortunately at odds with that provided by the authors of the book (i.e. -y (y+1) (3x+2) all over x (x+1) (y+2), and I don't know whether it's a misprint or my method is wrong.
  23. Calculus

    If f(x) = x ln(1+x) estimate the value of ln (2.1) given that ln2 = 0.6931.
  24. accounting

    Seurities Fair Value Adjustment (Trading) Account Securities Fair Value Adjustment (Trading) + (Gain) - (Loss) 25,000 Ending Balance 12/31/2009 Adjusting entry on 12/31/2010 35,000 Ending Balance on 12/31/2010 10,000 40,000 Adjusting entry on 12/31/2011 30,000 Ending Balance ...
  25. Westen Civ.

    Which governmental bodies are responsible for making laws in the United States? How does a written law protect American democracy?
  26. History on WW1

    How did President Wilson use Russia's democratic revolution to gain support for the war?
  27. stat math

    Stat hw question help me please? In a high profile murder case a sample of the general public's opinions concerning the guilt or innocence of the defendant is taken. A sample of n=100 males results in 62% of the respondents beliving that the defendant is guilty, while a ...
  28. math

    A random sample of the houses in a particular city is selected and each of the houses in a particular city is selected and each of the house's level of radon gas is measured. The values collected are given in the table below in parts per million (ppm). 4 8 13 6 7 3 9 8 11 ...
  29. statistics

    what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25 and 5 d. 5 and 1.25 e. 25 and square root of 5 ...