Tony and his brother can paint a building in 30 hours. How long will it take Tony to paint the building, if his brother can do the job in 45 hours?
Please explain how u get the answer!
2007-01-17 23:02:43 · 8 answers · asked by Unknown User 2 in Education & Reference ➔ Primary & Secondary Education
What they are saying is that them working together averages 30hrs, We already know Tony's Bro can average 45hrs by himself, we are trying to find out what Tony could do by himself, so plug in everything u have.
(Tony's "Average" + Bro's "Average")/2 = 30
in other words...
(x+45)/2 = 30
(take the 2 over to the other side and multiply by 30, which will equal 60, then bring 45 over by subtracting it and you'll get x)
x = 15
Tony could do the work by himself in 15hrs.
Now this depends on how smart the book you're using actually is, this is like if they lookin for average answers, because in real life, this wouldn't really make too much sense, because you really don't "average" speed of work, the correct answer is the one couple blocks above me... 90hrs
2007-01-17 23:16:22 · answer #1 · answered by I am using the 32 characters ari 2 · 1⤊ 0⤋
tony's brother can paint a building in 45 hrs
total painting done by him in 1 hr.=1/45
so in 30 hrs he can pain =1*30/45 building=2/3 building
so in 30 hrs painting done by tony=1/3 of the whole building
so total time taken by tony to complete the painting=30*3=90 hrs
2007-01-17 23:10:46 · answer #2 · answered by krissh 3 · 1⤊ 0⤋
no mathematician but logic says that tony's brother is faster. how much faster? he can paint 2/3 of the building in 30 hours, there for if they paint together, in 30 hours tony only paints a 1/3. for tony to paint the entire building, therefore it takes 90 hours.
2007-01-17 23:41:58 · answer #3 · answered by lonewolf07 2 · 0⤊ 0⤋
This is a Work Problem related:
Answer is 90 hours.
1/A + 1/B = 1/30 equation 1
1/B = 1/45 equation 2
therefore: A= 90 hours
2007-01-17 23:31:29 · answer #4 · answered by Jonathan 1 · 0⤊ 0⤋
60 hours because together they are only 15 hours faster so that means tony can only paint 1/3 as fast as his brother so one third of 45 is 15 and 45 + 15+ 60
Edit: actually if he is one third as fast it would be 45X3=135
2007-01-17 23:11:17 · answer #5 · answered by Grant B 3 · 0⤊ 1⤋
The correct answer is A because metals give some electrons to other elements when they form unions so they have less electrons than protons thus they have a positive charge and they are positive ions. Non-metals need to take some electrons so they have less protons than electrons and they form negative ions.
2016-05-24 02:52:35 · answer #6 · answered by Anonymous · 0⤊ 0⤋
he will take 15 hrs. equation is simple. the avg work
30 = 45+x/2
30*2=45+x
60-45=x
x=15 hrs
simple
2007-01-17 23:10:34 · answer #7 · answered by Anonymous · 0⤊ 1⤋
Do ur own freakin homework!!!!!
2007-01-17 23:31:23 · answer #8 · answered by papabeartex 4 · 1⤊ 0⤋