At the bird park were some adults.
13 of the number of locals was equal to 2 times the number of tourists. When another 13 tourists entered and 42 locals left, the ratio of the number of locals to the number of tourists become 7 : 2. Find the number of tourists at the bird park 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 |
- 84 |
- 42 |
+ 13 |
+ 91 |
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 - 84 = 7 u + 91
12 u - 7 u = 91 + 84
5 u = 175
1 u = 175 ÷ 5 = 35
Number of tourists at the bird park at first
= 1 u
= 35
Answer(s): 35