Muyaldeerson's time calculation

Algebra Level 1

One afternoon, Rose observes that the time that has elapsed since noon is equal to half the time that remains until midnight. What time is it?

This problem is posed by Muyaldeerson.

Details and assumptions

If your answer is 1:23pm, enter it as 123.


The answer is 400.

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Arron Kau by Arron Kau

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3 solutions

12pm-xpm

elapsed time=x hrs

xpm-12am

elapsed time=2xhrs

12pm-12am

elapsed time=12hrs =3xhrs

x= 12 3 \frac{12}{3} =4

The time is 4:00pm,so the answer is 400.

1 Helpful 0 Interesting 0 Brilliant 0 Confused
Kho Yen Hong
Aug 4, 2013

let the time from noon to midnight be a line AB with a length of 12, and the time on that moment be a point C, which cut the line AB with a ratio of 1:2. then we can easily find that AC is equal to 4, that result the time be 4.00pm

1 Helpful 0 Interesting 0 Brilliant 0 Confused

Same here. Maybe I should have answered "400" instead of just "4". O.O

Claudette Bartolome - 7 years, 10 months ago

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yes you should have

Livin Milton - 7 years, 10 months ago

I have wrote the same answer. Then why it is reported as incorrect?

Partha Roy - 7 years, 10 months ago

so why was that considered wrong when I answered it ?

Merna Magdy - 7 years, 10 months ago

let the time is x.so,12-x=2x, 12=3x, x=4......so the result is 4...

Pronab Malaker - 7 years, 10 months ago

I think a few people are falling into the trap writing 4 instead of 400, it really isn't obvious that 400 is the desired format to represent 4 pm.

Hanriette Bongo - 7 years, 10 months ago

if the answer is 1:23pm, enter as 123. same here, the answer is 4:00pm, then enter it as 400

Kho Yen Hong - 7 years, 10 months ago

ahh olryt, tnx!

Jervis Sajise - 7 years, 10 months ago

now i know!!!

Pearly Jane Mercado - 7 years, 10 months ago

now i know!

Pearly Jane Mercado - 7 years, 10 months ago

why AB line cut with ratio of 1:2

Mehwish Noor - 7 years, 10 months ago
Samagra Sharma
Aug 7, 2013

suppose time elapsed = x <br> then time remaining = 2x <br> therefore x + 2x = 12 <br> which gives x = 4

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