At the zoo were some adults.
12 of the number of tourists was equal to 2 times the number of locals. When another 31 locals entered and 11 tourists left, the ratio of the number of tourists to the number of locals become 7 : 3. Find the number of tourists at the zoo at first.
|
Make p the same (1)x3 = (3) |
Tourists (1) |
Locals (2) |
Make p the same (2)x7 = (4) |
Before |
12 u |
4 u |
1 u |
7 u |
Change |
- 33 |
- 11 |
+ 31 |
+ 217 |
After |
21 p |
7 p |
3 p |
21 p |
12 of the tourists = 2 times of the locals
1x22x2 of the tourists =
2x11x1 of the locals
Make the numerators the same. LCM of 1 and 2 is 2.
24 of the tourists =
21 of the locals
Tourists : Locals = 4 : 1
Make p the same.
(3) = (4)
12 u - 33 = 7 u + 217
12 u - 7 u = 217 + 33
5 u = 250
1 u = 250 ÷ 5 = 50
Number of tourists at the zoo at first
= 4 u
= 4 x 50
= 200
Answer(s): 200