Tutor MathsGuru: Ask me for your burning Maths questions!

[trytry]

I need help with this problem.


Alice is going up an escalator.
When she takes 2 steps per second, she reaches the top in 24 steps.
When she takes 1 step per second, she reaches the top in 16 steps.
How long will she take to reach the top if she just stands on the escalator?

TIA!

[kwcllf]

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[singmathstutor]

firebird:

Dear Singmathstutor


Good morning.

Many thanks for your detailed answer.

With best regards
Firebird

You're welcome, firebird

[singmathstutor]

blessedami:

Hi Firebird, No problems at all \" To err is human\"


Thanks dharma and Singmathstutor- glad that he got the answer correct, but now I can see clearly that the way you guys explain is very detailed while he is thinking from a student's point of view.

Thanks CJM- he is a P6 student.

We gotta be detailed because we're in this profession. However, the clearer and better way is to do model drawings....which is kinda difficult here

[CoffeeCat]

trytry:

I need help with this problem.


Alice is going up an escalator.
When she takes 2 steps per second, she reaches the top in 24 steps.
When she takes 1 step per second, she reaches the top in 16 steps.
How long will she take to reach the top if she just stands on the escalator?

TIA!

May I know what's the source of this question?
Questions similar to this have appeared twice in HCI's SMOPS so far.

First notice that the first scenario is completed in a faster time.
So by the time the Alice reached the top in the first scenario, 12secs have passed, and Alice will have covered 24 steps and let the escalator covered n steps.
In the same time but in th second scenario, Alice would have covered 12 steps only (half the speed) and escalator covered n steps.
In the next 4 secs, Alice would have to cover 4 steps (16-12), and the escalator will covered 8 steps (24-16).
Because 12 secs = 3 times 4 secs, the n steps = 3*8 = 24 steps.
So the total number of steps to be covered = 24 + 24 = 48 steps.
Now for the speed of the escalator, it covered 24 steps in 12 secs (first scenario), therefore speed is 2 steps/sec. Therefore time taken if Alice stands still is 48/2 = 24 secs.

[Almighty]

Hi all,


Can anyone help to let me know whether my answer to the follwing question is right?

Yao has 2 clocks in his house; a cuckoo clock and a pendulam clock. Unfortunately,\t\t
neither is in good working condition.The cuckoo clock gains 5 seconds for every minute \t\t
it runs (which means it gets faster and faster) whilst the pendulam clock loses 5 seconds\t\t
every minute it runs (which means it gets slower and slower).Yao resets both at 6 O’clock\t\t
in the morning. When the time shown on the pendulam clock is 7.am, what time is shown on the \t\t
cuckoo clock?

(My ans : 7.10.25 am (7-hr.10 - min and 25 secs in the morning. Am I correct?)

[biscuitqueen]

Mary and Ken travelled from Town A to Town B. Mary left Town A at 0915 and took 4h to reach Town B. Ken left Town A at 1000 and took 2h 45min to reach Town B. At what time did Ken pass Mary?

[trytry]

CoffeeCat:

trytry:

I need help with this problem.


Alice is going up an escalator.
When she takes 2 steps per second, she reaches the top in 24 steps.
When she takes 1 step per second, she reaches the top in 16 steps.
How long will she take to reach the top if she just stands on the escalator?

TIA!

May I know what's the source of this question?
Questions similar to this have appeared twice in HCI's SMOPS so far.

A math test taken by student for DSA selection

[Cheerfuldad]

Dear all,


Please help!

P5 Question:

Q. Four girls, Alice, Bibi, Carol and Delia, each have some stickers. the number of stickers Alice has is 1/2 of the total number of the stickers Bibi, Carol and Delia have. The number of stickers Bibi has is 1/4 of the number of stickers Alice, Carol and Delia have. The number of stickers Carol has is 2/3 of the total number of stickers Alice, Bibi and Delia have. If Delia has 30 stickers, Find the total number of stickers Bibi and Carol have altogether. :?:

TIA

[mujin]

Cheerfuldad:

Dear all,


Please help!

P5 Question:

Q. Four girls, Alice, Bibi, Carol and Delia, each have some stickers. the number of stickers Alice has is 1/2 of the total number of the stickers Bibi, Carol and Delia have. The number of stickers Bibi has is 1/4 of the number of stickers Alice, Carol and Delia have. The number of stickers Carol has is 2/3 of the total number of stickers Alice, Bibi and Delia have. If Delia has 30 stickers, Find the total number of stickers Bibi and Carol have altogether. :?:

TIA

Let me try..

Alice = (1/2)/(1+1/2) = 1/3 of total
Bibi = (1/4)/ (1+1/4) = 1/5 of total
Carol = (2/3)/(1+2/3) = 2/5 of total
Delia = 1-[(1/3)+(1/5)+(2/5)] = 1/15 of total = 30 stickers
Total stickers = 30x15 = 450

Ans
Bibi has 450 x (1/5) = 90
Carol has 450 x (2/5) = 180

Bibi + Carol = 90+180 = 270 stickers