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Four families have four children each, find the probability that at least one of the families have two boys and two girls? The answer is around 0.8.....

A shop sells cds. Rent is $400 per week. other ongoing cost total $200 per week. some cds they buy cost $8, some cost $12, some cost $16. They charge 50% more per cd when they sell them tahn when they buy them. This is their profit? Assume they sell twice as many $8 cd as $12 cds, and twice...

In a psychology experiment, a rat is placed in the maze shown in the figure. In each minute of the observation, the rat may stay in the room it is in, or move to by any of the exits to another room. For all rooms the probability of remaining in the room is 40%, reflecting the fact that rats...

There was a total of 134 questions, and like maybe 48 questions were about category 1, 44 questions on category 2 and 44 question on category 3. I got 23/48 right answers for category 1 and 30/44 and 22/44 for category 2 and 3 respectively? What would be my percentile or score?

Why is Titanium's atomic size smaller than Polonium? using electron configuration and nuclear charge.

From past records it has been found that the cost rate of maintaining a certain car is dc/dt = 75t^2 +50t + 800 where C is the accumulated cost in dollars and t is the time in years since the car was first used. Find: the maintenance cost for the second year? The answer is $1050 ?? but i...

How many electrons are present in the 2p orbitals of a neutral fluorine atom? The answer is 3 but why? i thought it was 5?

How to find the exact area of this region that lies below 1/ (4x^2 +1) and above 1/(x^2 +4)?

For curve x^2 =4ay shade the region bounded by the curve and the latus rectum. Find the volume of the solid generated when the region is rotated about the axis of symmetry?

I was wondering for a student that receives course scores above 85-90 and is within the top 10% of the college, would a student lose that rank in the college if they individually did not so well in the AST Test. I have been told by college teachers that the top 10% and the bottom 10% of the...

How do we integrate xln(x)? steps? I tried something like u' = x and v'= in(x) which means u = x^2/2 and v .

r(t) = [2sin(t)cos(t)]i + 2sin^2(t)j x(t) =2sin(t)cos(t)] y(t)=2sin^2(t) ??

r(t) = 2tan(t)i + 2cos^2(t)j I guess x(t) = 2tan(t) and y(t) =2cos^2(t) ??

How do we Find the value of k for which the line y=kx bisects the area enclosed by the curve 4y=4x-x^2? I tried to find the area enclosed by the curve which was 8/3 unit squared, then I halved that to get 4/3. I then try integrating the y=kx and equating that to 4/3 but the answer i...

A function y = 12x-32-x^2 has x intercepts of 4 and 8. A tangent to this curve has equation of y=2x-7 at point A where x =5. If the tangent meets the x axis at B, and C is the x intercept of the parabola closer to the origin, find the area of the region bounded by AB, BC and arc CA? The...

!Which reactant to use to calculate the amount of heat released or absorbed? Does it matter? I tried to find the mols of NH4SCN and then multiplied it with the delta H. but the answer used barium hydroxide instead??? 50 g NH4SCN is mixed with slight excess barium hydroxide, and the delta...

Methane gas, CH4 t readily burns in air to produce carbon dioxide and water vapour. If all gas volumes are measured at STP calculate: (a) the volume of oxygen gas which is required for the complete combustion of 12.5 L of methane gas (b) the volume of air required for reaction, given...

Can the magistrate court make common laws?

Plane travels at a speed of 240km/h when there's no wind. Today there's wind velocity of -3i -7j km/h. Speed of the wind is 7.62 km/h. What is the working out of the position vector required if the pane is to end up due east of its starting position after 2 hours? The Answer is: 486i +...

another aeroplane can travel at a speed of 240km/h when there's no wind. Today there's a wind velocity of -3i -7j km/h. The speed of the wind is 7.62 km/h. Find the position vector required if the aeroplane is to end up due East of its starting position. What would this look like in a diagram?