Answer:
1.5 hours
Step-by-step explanation:
Given :
My hose = 3 hours ; my rate = 1/3
Let My friend's time = x ; his rate = 1/x
Combined time = 1 hour, combined rate = 1/1 = 1
Combined rate :
1/3 + 1/x = 1
1/x = 1 - 1/3
1/x = (3 - 1)/ 3
1/x = 2/3
Cross multiply :
3 = 2x
x = 3/2
x = 1.5 hours