+20 There were 5/8 as many shells as fish in an aquarium. After 50 shells and 8 fish were removed, the ratio of the number of shells to the number of fish became 1:4. Find the number of shells in the aquarium in the end.
+37148 f = fish #
5/8 f = shell number
(5/8f -50) / (f-8) = 1/4 <==== solve for f ....cross multiply to get:
4 ( 5/8f-50) = f-8
20/8f - 200 = f-8
12/8 f = 192
f = 128
then ORIGINAL shells were 5/8 (128) = 80
FINAL shells = 80 - 50 = 30 shells in the end
+10 S: 1p = 5u - 50
F: 4p = 8u - 8
1p = 2u - 2
5u - 50 = 2u - 2
3u = 48
1u = 16
Shells in the end = 2(16) - 2.
Number of shelsss in end = 30
