Wednesday

January 28, 2015

January 28, 2015

Posted by **muffy** on Saturday, September 12, 2009 at 12:31pm.

Please let me know if I am correct.

First I took the average of 4 and 7 and got 5.5 hours. So they can both paint the room in 5.5 hours.

Next, If they start at 9:30 they will finish at 3:00

Next if they have to leave 45 minutes early to get to a 12:00 show, they should leave at 11:15.

Next, therefore, they will be 3:45 minutes late for the 12:00 show.

- math -
**bobpursley**, Saturday, September 12, 2009 at 12:47pmYou cant trust the average always.

I assume you are using a rate equation,

amount=rate*time

Consider in 28 hours, shelby can paint 7, and Zoe can paint 4. So the combined rate = (7+4 rooms)/28 hrs= 11/28 rooms/hr

Now the time to paint one room

amount= rate*time

time= amount/rate= 1room/(11/28 room/hr)

time= 1*28/11 hrs= 2.54hrs= 2hrs 33min

If they start at 9:30, then they finish about three min after noon. Check my thinking and calculations.

Now on your thinking... Using the average 5.5hrs per room, but BOTH are working, that is the average for each, so time for both together would be 5.5/2= 2.75hrs, which is not 28/11 hrs (2.545hrs). SO dont use the average, throw away that thinking, it wont work.

- math -
**muffy**, Saturday, September 12, 2009 at 1:26pmThank you soooooooo much, you are a great teacher! I truly understand!

**Answer this Question**

**Related Questions**

Intermediate Algebra - Joe can paint a room in 6 hours while Sue can paint the ...

math - If painter A can paint a room in three hours by themselves, and painter B...

math question grade 8!! - shelby wants to paint the walls and ceiling of a ...

math - nadia can paint a room in 5 hours Nat can paint the same room in 7 hours ...

math - Arthur can paint a room in 6 hours. Boris can paint the same room in 8 ...

Algebra - If Dale can paint a room in 5 hours alone and Chip can paint the same ...

math - A can paint a room in 3 hours, and B can paint a room in 4 hours. How ...

Math - Al can paint a room in a hours working alone. Bill can paint a room in b ...

math - If jen can paint a room in 7 hours and jen and keith can paint the room ...

algebra 2/trig - Tina can paint a room in 8 hours, but when she and her friend ...