Algebra Question for Title 1 Schools: How Long Question?
2) If Anne can paint a room in 4 hours and Peter can do the same in 6 hours, how long will it take both of them working together?
distance = rate x time
rate = distance / time
1/4 + 1/6 = 1/x (we add because they are working together; the room is the numerator and their hours denominator)
The LCM of 4 (2 x2) and 6 (2×3) = 12 because you take the longest chain of each number (2x2x3 = 12). Then you divide the LCM by each denominator and multiple each answer with their respective numerator.
(3 + 2)/12 = 1/x
5/12 = 1/x
you have to make “x” subject of formula by moving “x” to the other side to make it a numerator. When you go to the other side, addition becomes subtraction, multiplication becomes division, and vice versa.
x/1 = 12/5
x = 12/5 = 2 2/5
2/5 of 60 minutes = 24 minutes
x = 2 hours 24 minutes for both Anna and Peter to paint the room together.