Very simple algebra problem, please help!?
One guy can paint a house in 6 hours. The other guy can paint it in 4 hours. How long will it take to paint a house if they work together?
This seems very simple but I just can't get it.
One guy can paint a house in 6 hours. The other guy can paint it in 4 hours. How long will it take to paint a house if they work together?
This seems very simple but I just can't get it.
Comments
1st guy has painting work rate 1/6 houses per hour
2nd guy has painting work rate 1/4 houses per hour
If we denote the time taken to paint the house x hours and set the number of houses as 1
Use formula: painting rate (houses/hr) x time taken (hrs) = number of houses painted (houses)
for 1st guy: 1/6*x=1 ----> x=6 hours
for 2nd guy: 1/4*x=1 ----> x=4 hours
together: 1/6*x +1/4*x =5/12*x ----> x=12/5 hours
x=2.4 hours
let guy is A & B
A's work of 1 hour = 1/6
B's -----------------------= 1/4
both together in 1 hour paints = 1/6+1/4 = 10/24
so total work by both together in = 24/10 = 2.4 hours
i.e. in 2 hour & 24 minutes ANSWER