At the zoo were some adults.
13 of the number of locals was equal to 2 times the number of tourists. When another 20 tourists entered and 25 locals left, the ratio of the number of locals to the number of tourists become 7 : 2. Find the number of tourists at the zoo at first.
|
Make p the same (1)x2 = (3) |
Locals (1) |
Tourists (2) |
Make p the same (2)x7 = (4) |
Before |
12 u |
6 u |
1 u |
7 u |
Change |
- 50 |
- 25 |
+ 20 |
+ 140 |
After |
14 p |
7 p |
2 p |
14 p |
13 of the locals = 2 times of the tourists
1x23x2 of the locals =
2x11x1 of the tourists
Make the numerators the same. LCM of 1 and 2 is 2.
26 of the locals =
21 of the tourists
Locals : Tourists = 6 : 1
Make p the same.
(3) = (4)
12 u - 50 = 7 u + 140
12 u - 7 u = 140 + 50
5 u = 190
1 u = 190 ÷ 5 = 38
Number of tourists at the zoo at first
= 1 u
= 38
Answer(s): 38