I need someone help with a Mathematics question
January 28, 2007 3:40am CST
Here is the question: How many minutes before 12 noon is it if 72 minutes ago it wastwice as many minutes past 9 am?
• Sri Lanka
28 Jan 07
To do this first we must convert the time into minutes of the day. 9 am will be (9x60) 540th minute of the day, and 12 noon will be (12x60) 720th minute of the day. The minute time now is X. 7 72 minutes ago it was X-72. Since it is X minutes now the number of minutes past 12 is X - 720. Twice this amount is 2X - 1440 I is said that 72 minutes ago it was 9 past twice (X-720) So X -72 = 540 + (2X-1440) We will simplify this using Algebra. X - 72 = 540 + 2X - 1440 X - 2X = 540 - 1440 + 72 -X = -828 X = 828 So now we are in the 828th minute of the day. Divide this by 60 and we get 13 hours and 48 minutes. So now it is 1.48 PM. Check whether this is correct. 72 minutes ago it was 12.36 This is 216 minutes after 9 am. 1.48 pm is 108 minutes after 12 noon. So our calculation is correct.