At the museum were some adults.
12 of the number of locals was equal to 2 times the number of tourists. When another 20 tourists entered and 39 locals left, the ratio of the number of locals to the number of tourists become 5 : 3. Find the number of locals at the museum at first.
|
Make p the same (1)x3 = (3) |
Locals (1) |
Tourists (2) |
Make p the same (2)x5 = (4) |
Before |
12 u |
4 u |
1 u |
5 u |
Change |
- 117 |
- 39 |
+ 20 |
+ 100 |
After |
15 p |
5 p |
3 p |
15 p |
12 of the locals = 2 times of the tourists
1x22x2 of the locals =
2x11x1 of the tourists
Make the numerators the same. LCM of 1 and 2 is 2.
24 of the locals =
21 of the tourists
Locals : Tourists = 4 : 1
Make p the same.
(3) = (4)
12 u - 117 = 5 u + 100
12 u - 5 u = 100 + 117
7 u = 217
1 u = 217 ÷ 7 = 31
Number of locals at the museum at first
= 4 u
= 4 x 31
= 124
Answer(s): 124