When the Apex Pet Store first opened, the ratio of cats to dogs was 4 to 5. Since then, the number of cats has doubled, while the number of dogs has increased by 12. If the ratio of dogs to cats is now 1 to 1, how many cats did the store have when it opened?
2007-07-23 13:57:24 · 6 answers · asked by wu_4533 2 in Science & Mathematics ➔ Mathematics
4c=5d
2c=d-12
solve by substitution or elimination
2007-07-23 14:00:17 · answer #1 · answered by leo 6 · 0⤊ 0⤋
When opened
1) C/D = 4/5
C = 4D/5
Later
2C/(D + 12) = 1/1
2C = D + 12
Substitute from equation 1
2(4D/5) = D + 12
8D = 5D + 60
3D = 60
D = 20
1) C = 4D/5
C = 80/5
C = 16
Check
2(16) = 20 + 12
32 = 32
2007-07-23 21:07:55 · answer #2 · answered by kindricko 7 · 0⤊ 0⤋
c/d = 4/5 --> 4d= 5c --> d= 5c/4
2c/(d+12) = 1 --> 2c = d+12
Substitute d =5c/4 getting:
2c = 5c/4 + 12
8c = 5c +48
3c = 48
c = 16 = # of cats at opening
d = 5c/4 = 20 = # of dogs at opening
2007-07-23 21:09:47 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋
16 cats
2007-07-23 21:04:32 · answer #4 · answered by bluecollaraddict 3 · 0⤊ 0⤋
C/D = 4/5
2C / (D + 12) = 1
5C = 4D
D = 5C/4
2C = 5C/4 + 12
8C = 5C + 48
3C = 48
C = 16 cats
2007-07-23 21:16:32 · answer #5 · answered by romanmarkovich 1 · 0⤊ 0⤋
2c = d + 12 you mean?
2007-07-23 21:10:21 · answer #6 · answered by Anonymous · 0⤊ 0⤋