Question

A and b worked together on a job for 4 hours and finished half of it. A worked thrice as fast as b did. If b then left and a was joined by c and they finished the job in 1 hour, how long would it have taken c to do the whole job alone?

Answer 1

A+B=4HRS=1/2 WORK

A+B=8HRS=1 (FULL WORK )
1/A = 3/B
A+B=8HRS
1/(B/3) +1/B = 1/8
B = 32
1/A = 3/B 
1/A = 3/32

(3/32 +1/X ) = 1/2 WORK
SOLVING THIS 
WE GET 
X = 32/13 HRS ( i.e C )


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Answer 2

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here,

A/Q,

A+B = 4 hr

=1/2 work

again,

A+B = 8 hr

= 1 (total work )

now,

1/A = 3/B

A+B=8 hr

so,

1/(B/3) +1/B = 1/8

B = 32

1/A = 3/B 

1/A = 3/32

(3/32 +1/X ) = 1/2 WORK

after simplification ,

we get ,

X = 32/13 hr ( i.e C )


hope it helps U ❤️❤️

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