At the zoo were some adults.
12 of the number of tourists was equal to 3 times the number of locals. When another 19 locals entered and 21 tourists left, the ratio of the number of tourists to the number of locals become 7 : 2. Find the number of tourists at the zoo at first.
|
Make p the same (1)x2 = (3) |
Tourists (1) |
Locals (2) |
Make p the same (2)x7 = (4) |
Before |
12 u |
6 u |
1 u |
7 u |
Change |
- 42 |
- 21 |
+ 19 |
+ 133 |
After |
14 p |
7 p |
2 p |
14 p |
12 of the tourists = 3 times of the locals
1x32x3 of the tourists =
3x11x1 of the locals
Make the numerators the same. LCM of 1 and 3 is 3.
36 of the tourists =
31 of the locals
Tourists : Locals = 6 : 1
Make p the same.
(3) = (4)
12 u - 42 = 7 u + 133
12 u - 7 u = 133 + 42
5 u = 175
1 u = 175 ÷ 5 = 35
Number of tourists at the zoo at first
= 6 u
= 6 x 35
= 210
Answer(s): 210