At the concert hall were some adults.
12 of the number of tourists was equal to 2 times the number of locals. When another 72 locals entered and 9 tourists left, the ratio of the number of tourists to the number of locals become 5 : 4. Find the number of locals at the concert hall at first.
| |
Make p the same
(1)x4 = (3) |
Tourists
(1) |
Locals
(2) |
Make p the same
(2)x5 = (4) |
| Before |
16 u |
4 u |
1 u |
5 u |
| Change |
- 36 |
- 9 |
+ 72 |
+ 360 |
| After |
20 p |
5 p |
4 p |
20 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)
16 u - 36 = 5 u + 360
16 u - 5 u = 360 + 36
11 u = 396
1 u = 396 ÷ 11 = 36
Number of locals at the concert hall at first
= 1 u
= 36
Answer(s): 36
