Question

If x varies directly with y and x = 2.5 when y = 10, find x when y = 16.

Answer 1

in direct variation x1/y1 = x2/y2

so

2.5 x2 2.5 * 16
--- = ---- ==> ---------- = ? ==> 4 = x2
10 16 10

Answer 2

\[x = y/k\]
\[2.5=10/k\]
\[k=10/2.5=4\]

Answer 3

\[x=16/4=4\]

Answer 4

Or you could say:\[x=ky\]\[2.5=10k\]\[k=2.5/10=.25\]
\[x=.25 (16)=4\]
Same answer, but more user friendly.