Math Is Fun Forum

SweetKerry

Member

Registered: 2006-10-28

Posts: 3

Need answer for this problem

Problem: Fifty minutes ago, if it was four time as many minutes past three o'clock, how many minute is it to to six o'clock?

Hi, please help me to solve this problem

All_Is_Number

Member

Registered: 2006-07-10

Posts: 258

Re: Need answer for this problem

Problem: Fifty minutes ago, if it was four time as many minutes past three o'clock, how many minute is it to to six o'clock?

Hi, please help me to solve this problem

It is "now" 50+(50*4) = 250 minutes past three o'clock = ten minutes after seven o'clock.
That means that it will be six o'clock again in 650 minutes.

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You can shear a sheep many times but skin him only once.

polylog

Member

Registered: 2006-09-28

Posts: 162

Re: Need answer for this problem

I may quite possibly be wrong, but I interpret the problem like this:

let the current time be T minutes. T is measured in minutes.

let the number of minutes be 0 at noon.

Therefore, T is the number of minutes that have passed since noon.

Writing 3PM in terms of minutes past noon:

3PM = 3 * 60 minutes = 180 minutes

Translating the given information into an equation:

T - 50 = 4(180 + T)

Solving for T:

T - 50 = 720 + 4T

3T = -770

T = -256.667

Writing 6PM in terms of minutes since noon:

6PM = 6 * 60 minutes = 360 minutes

let X be the amount of minutes needed to get to 6PM from the current time.

We know now that:

-256.667 + X = 360

X = 385.667

Therefore it is about 386 minutes to six o'clock.

All_Is_Number

Member

Registered: 2006-07-10

Posts: 258

Re: Need answer for this problem

I may quite possibly be wrong, but I interpret the problem like this:

let the current time be T minutes. T is measured in minutes.

let the number of minutes be 0 at noon.

Therefore, T is the number of minutes that have passed since noon.

Writing 3PM in terms of minutes past noon:

3PM = 3 * 60 minutes = 180 minutes

Translating the given information into an equation:

T - 50 = 4(180 + T)

Solving for T:

T - 50 = 720 + 4T

3T = -770

T = -256.667

Writing 6PM in terms of minutes since noon:

6PM = 6 * 60 minutes = 360 minutes

let X be the amount of minutes needed to get to 6PM from the current time.

We know now that:

-256.667 + X = 360

X = 385.667

Therefore it is about 386 minutes to six o'clock.

I'm not seeing how you came up with the initial equation.

I'm also not clear how you ended up with a non-integer result (before rounding).

---

You can shear a sheep many times but skin him only once.

polylog

Member

Registered: 2006-09-28

Posts: 162

Re: Need answer for this problem

The statement is:

"Fifty minutes ago, if it was four time as many minutes past three o'clock"

I find the statement of the problem somewhat confusing. The way I interpret it is this:

"Fifty minutes ago" --> the current time minus 50 minutes

"if it was four times as many minutes past three o'clock" --> 'it' refers to the "fifty minutes ago" and it "was" [ie it was equal to] four times as many minutes past 3PM. This is how I got the equation. ie, "four times as many minutes past 3PM" -> 4 times the same number of minutes (the question says *as many*) past 3 PM, ie 3PM + T (but expressed in number of minutes). 

Again I think the problem statement is badly worded, could you tell me how you arrived at your interpretation from the original wording?

All_Is_Number

Member

Registered: 2006-07-10

Posts: 258

Re: Need answer for this problem

The statement is:

"Fifty minutes ago, if it was four time as many minutes past three o'clock"

I find the statement of the problem somewhat confusing. The way I interpret it is this:

"Fifty minutes ago" --> the current time minus 50 minutes

"if it was four times as many minutes past three o'clock" --> 'it' refers to the "fifty minutes ago" and it "was" [ie it was equal to] four times as many minutes past 3PM. This is how I got the equation. ie, "four times as many minutes past 3PM" -> 4 times the same number of minutes (the question says *as many*) past 3 PM, ie 3PM + T (but expressed in number of minutes). 

Again I think the problem statement is badly worded, could you tell me how you arrived at your interpretation from the original wording?

I also found the wording somewhat confusing.

I interpreted "Fifty minutes ago, if it was four time as many minutes past three o'clock" as 50 minutes ago it was 4*50 minutes past three o'clock, which meant the "current" time was 250 minutes past three o'clock, or ten minutes after seven o'clock. By that reasoning, it would be six o'clock in ten hours and fifty minutes, or 650 minutes.

I want to emphasize that I am not claiming you are incorrect; I just did not understand your interpretation of the problem.

---

You can shear a sheep many times but skin him only once.

polylog

Member

Registered: 2006-09-28

Posts: 162

Re: Need answer for this problem

Ok I see now, it should be read as:
"Fifty minutes ago, if it was four time as many minutes past three o'clock" = 50 minutes ago, it was four times as many minutes (ie *4 times as much as that 50 minutes*) past 3 o'clock.

I agree now, this is probably how it should be interpreted. It's not as convoluted. But I still think it's a badly worded problem.

SweetKerry

Member

Registered: 2006-10-28

Posts: 3

Re: Need answer for this problem

I think the equation must be T - 50 = 180 + 4T where T is the current time.

Last edited by SweetKerry (2006-10-31 04:56:41)

polylog

Member

Registered: 2006-09-28

Posts: 162

Re: Need answer for this problem

That was my very first interpretation actually, and I got 436.667 minutes to 6PM.
But All_is_number's interpretation seems most natural, plus it doesn't give non-integer answers.