1. Mercury is almost two times as dense as iron. (Mercury is twice as dense as iron)
2. Alcohol is 80% of the density of water.
3. .
4. The density of most objects vary from air which has a density of 0.00129 grams per cubic centimetre (g/cc) to mercury which has a density of 13.60g/cc. Notice that mercury is by far the heaviest with the next heaviest being iron which is half as dense a mercury. Water provides a useful benchmark of 1 g/cc, so you can see easily for example that alcohol is 81% of the density of water.

1.  His BAC after 1 hour = 0.05398-0.012 x 0.5 = 0.048
2. 
3. Her BAC is initially 0.1013. The female can drive home after about 4 hours.
4. Even though the male and female have drunk the same quantity of alcohol, the female's BAC is about double the males'. While the male can drive home after one hour the female has to wait at least 4 hours..
1. .
2.  
3. The slope of the line from 1977 to 1997  = 0.2 millions of computers per year; The slope from 1997 to 2050 is 0.12 millions of computers per year. The rate of increase in computer ownership between 1997 and 2050 is predicted to be almost half that of 1997 to 1997.

4. Let x be the number of kilograms of Coffee A and y be the number of kilograms of Coffee B. Since there are 60kg altogether, one equation will be x + y = 60. Each kilo of coffee A costs $15 so the total for Coffee A will be $12x and each kilo of coffee B is $17 so the total for coffee B is $17y. The total cost of the coffee will be 60 times $15. So the second equation will be 15x + 17y = 90

x = 24, y = 36

5. EZI English increased by 27% while EZI Maths increased by 5.8%, so EZI English has provided a better return.

 

6.  a    the mean = $33600, median = $29000 and modal wage = $12000

        c     The standard deviation is 31.0. If the 125 were reduced to 25 this would make the standard deviation a lot smaller since standard deviation is a measure of spread from the mean and the data would be less spread out.

7.    Solutions to level C