Two people, Ali and Bali, are at the bottom floor and they start climbing the stairs at the same time. Ali climbs two times as fast as Bali. If Bali reaches the fifth storey, where is Ali now?
The answer is 5x2-1=9 but I don't understand it. I thought it is 10??
2007-11-29 00:39:10 · 11 answers · asked by lol 1 in Science & Mathematics ➔ Mathematics
Assuming the number of steps for each floor do not change and the speed remains the same and some other logical assumptions
2007-11-29 00:41:12 · update #1
o i think i got it
2007-11-29 00:50:42 · update #2
thanks to the joe
2007-11-29 00:51:04 · update #3
I forgot about the fact that they were starting at floor 1
2007-11-29 00:51:40 · update #4
thanks everyone for your help
2007-11-29 00:56:08 · update #5
I also felt that the question isn't phrased properly but what can we do
2007-11-29 00:59:27 · update #6
Let Bali's speed be x
Ali's speed is 2x
t = d / v
t(bali) = d(b) / x = 5/x
t(ali) = d (a)/ 2x
since they climb the same time, there times are equal:
t(bali) = t(ali)
5 / x = d(a) / 2x
Solving this gives you d = 10
so he would be on the tenth floor if they started from floor 0. However they started form one, therefore he is one the ninth floor.
or: Bali's distance is 4 (he is on the fifth, but started from one), therefore Ali's distance is 4 x 2 = 8. first floor + 8 floors gives you floor number 9.
Hope it helps
2007-11-29 00:44:04 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Both start on floor 1. This is whats messing you up. Ali goes to floor 3 and Bali to floor 2. Then Ali goes to 5 and Bali to 3, then Ali to 7 and Bali to 4, Ali to 9 and Bali to 5. So the answer is floor 9 and 5.
2007-11-29 08:49:33 · answer #2 · answered by The Joe 3 · 0⤊ 0⤋
It's not (5 x 2) -1 =9.
Bali only climbed 4 flights; he went from floor 1 to floor 5.
Therefore, Ali climbs twice as fast, so she climbed 8 flights, so she went from floor 1 to floor 9.
So the equation is (4 x 2)+1=9.
2007-11-29 09:25:29 · answer #3 · answered by student 2 · 0⤊ 0⤋
The bottom floor is floor 1. you have to take that out of the equation. You don't climb to floor 1.
Ali and Bali, both on floor 1.
Ali is on 3 when bali is on 2
ali is on 5 when bali is on 3
ali is on 7 when bali is on 4
ali is on 9 when bali is on 5
Hope that helps.
2007-11-29 08:48:06 · answer #4 · answered by ijump82 2 · 1⤊ 0⤋
both starts at the bottom floor, when Bali reaches the 5th floor he should have climbed 4 stories,Ali is climbing two times faster , so he should climb 4 x2 = 8 stories,so he should be in the ninth floor
2007-11-29 08:50:54 · answer #5 · answered by Anonymous · 0⤊ 0⤋
No, the answer is correct. When Bali REACHES the fifth storey, he has climbed four. Therefore, Ali has climbed eight storeys, and has therefore reached the ninth.
2007-11-29 08:52:30 · answer #6 · answered by AndrewG 7 · 0⤊ 0⤋
It is rather a interpretation problem.
If the first floor is one up from the bottom (ground floor) then the answer is 10.
If the first floor is considered to be on ground level or bottom the answer must be one less.
If a single basement is considered the bottom. . . . well you get what I mean.
I think you should carefully read the question again.
2007-11-29 08:59:28 · answer #7 · answered by watergump44 4 · 0⤊ 0⤋
5x2 is 10
10-1 is 9 that's how they got the answer
or are you confused on how they got the 5x2-1
2007-11-29 08:44:02 · answer #8 · answered by Ali 3 · 0⤊ 0⤋
The answer is 10. You just multiply 5 *2. I think someone is trying to mess with you. The answer is 10.
2007-11-29 08:44:28 · answer #9 · answered by fairmonths_2007 1 · 0⤊ 0⤋
unless they changed the way to count
then the answer is 10
it doesnt say they started on floor 1 anywhere , so it is presumed they start on the ground floor
if that is the answer then the question isnt phrased properly
all the best
Ian
2007-11-29 08:49:42 · answer #10 · answered by Anonymous · 0⤊ 0⤋