If r varies inversely with w - 1. If r = 3/50 when w = 3, find r when w is 10.
A 75
B 10
C 175
D 1/75
E 1/750
F 1/175
2007-06-04 04:31:02 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
r = k/(w-1)
3/50 = k/(3 - 1)
3 * 2 = 50k
6 = 50k
k = 6/50 = 3/25
Therefore r = 3/(25* (w-1))
when w = 10
r = 3/(25 * (10-1))
r = 3/ (25 * 9)
r = 1/75 (D)
2007-06-08 04:12:20 · answer #1 · answered by topsyk 3 · 0⤊ 0⤋
"r varies inversely with w-1" This basically means that r is proportional to 1/(w-1), or r=k/(w-1), where k is some constant that we need to determine.
To do this, what do we know? Well, r=3/50 when w=3, plugging this in to our equation for r...
r=k/(w-1)=k/(3-1)=k/2=3/50
Therefore... k=6/50. Now we know the equation for r...
r=6/[50*(w-1)]=3/[25*(w-1)]
The question asks what is r when w is 10, when you work this hopefully you'll see the answer is D.
2007-06-04 11:40:55 · answer #2 · answered by deken_99 2 · 0⤊ 0⤋
r = k/(w - 1)
3/50 = k / 2
k = 3 / 25
r = (3/25) / 9
r = 1 / 75
ANSWER D
2007-06-04 13:26:18 · answer #3 · answered by Como 7 · 0⤊ 0⤋