Step-by-step explanation:
Alrighty! here you go image.
Answer is 18 unless u wont it in letters
I remember CUP -- concave up positive. Here we have a leading coefficient that's negative, so the cup is upside down, the parabola opens down, an arch not a bowl.
How much part can sally paint in an hour ?
a ÷ 7 = a/7
And what about Steve ?
a ÷ 9 = a/9
Where, a is the total area of the room.
So, let the time taken by both of them to paint the room together be 't'
So,
t(a/7 + a/9) = a
t(9a/63 + 7a/63) = a
t(16a/63) = a
t = 63/16 ≈ 4 hr
