Posted by Rick on .
I am having a lot of difficulty trying to figure out how to put two math (word problems) questions into an expression. Can someone help me, I can do the rest from there. An explanation on the math formula would be great too.
here's the two questions.
1. The projected number of men and women enrolled in US colleges, in millions, is modeled in the following formulas: Women: N=0.007x+4.1 Men: N=0.01x +3.9
What is the project enrollment of women in 2004, and what is the projected enrollment of men in 2004?
2. The water level of a reservoir is measured over a 5month period of time. At the beginning, the level is 25ft. During this time, the level fell 3 ft., then rose 2ft., the rose 1 foot, then fell 4ft., and then rose 2ft. What is the reservoir’s level at the end of the 5month period?

algebra 
Reiny,
1. Unless we know the definition of x, .... ?
If x is the time in years, just plug in the values of 2004 into both equations.
2. What is 25  3 + 2 + 1  4 + 2 
algebra 
Rick,
The projected number of men and women enrolled in US colleges, in millions, is modeled in the following formulas: Women: N=0.007x+4.1 Men: N=0.01x +3.9
N represents enrollment, in millions, x years after 1984 (I left this part out last posting).
What is the project enrollment of women in 2004, and what is the projected enrollment of men in 2004?
With x equaling years after 1984, should I subtract 1984 from 2004 to get 20 years then multiply this by 0.007 for the women? What is the +4.1? Do I multiply 4.1 times 20 years also? I’m not sure how to put this into an equation. My guess:
N=20*.007+20*4.1=222 
algebra 
Reiny,
yes, for 2004, x = 20
but you substituted incorrectly
the 4.1 in a constant in millions and it was the enrollment in 1984
The 4.1 has no variable with it to substitute, (that's why it is called a constant)
(note that for 1984, x = 0, and
N = .007(0) + 4.1 = 4.1
for 2004, the women's enrollment is
N = .007(20) + 4.1 = 4.24
so there are 4,240,000 women enrolled
Do the same for the Men equation.