Alan

I think the questioner means express as a ratio .

\(502.5=502+\frac{1}{2}=\frac{1004+1}{2}=\frac{1005}{2}\)

The following should help:

(a)  \(100(\frac{22}{7} - \pi)/\pi = 0.04\%\) 

I'll leave you to do (b) in the same way.

Correct!  Search for the Clay Institute Millenium problems for the details.

This is the Riemann hypothesis and no mathematician has yet either proven or disproved it!

I get the following:

(Note to billyzhang:  The question specifies integer coefficients, which your A and B are not.)

Original price   x

Price in 2001   0.8*x

Price in 2002  0.8*0.8*x

Price in 2003    f*0.8*0.8*x = x  so f = 1/(0.8*0.8) = 1.5625  

I'll let you work out the percentage increase from here.

For equation \(ax^2 + bx + c = 0\)  to have repeated roots we must have \(b^2 - 4ac = 0\)

Calculate this for each quadratic in turn.

Add the two equations together.  Divide both side of the result by 4 to get x+y+z, then divide by 3 to get the average.

See https://web2.0calc.com/questions/help-please_83718#r1