<PRE><B>Question 1028038</B>
Hi there,
Make treadmill = x
and elliptical = y
x + y = 30............(1)
12x + 8.5y = 325......(2)
Multiply Eq(1) by 8.5
8.5x + 8.5y = 255.....(1)
12x + 8.5y = 325......(20
Subtract Eq(1) from Eq(2)
3.5x = 70
x = 20
Substitute x = 20 into
Eq(1)
x + y = 30
20 + y = 30 
y = 30 - 20
y = 10
The athlete spends 20 minutes
on the treadmill and 10 minutes 
on the elliptical.
Hope this helps :-)</PRE>