Time and Work Practice Test 1 with solutions

Question : 1 of 40

Marks: +1, -0

Two persons A and B can complete a piece of work in 8 hours and 16 hours respectively. If they work at it alternately for an hour, A starting first, in how many hours will the work be finished?

$9 1/3$ hours
$10 1/2$ hours
$11 1/2$ hours
$8 1/2$ hours

Validate

Solution:

In 2 hours the part of work =

1/8 + 1/{16}

3/{16}

will be completed.
Hence, in 5 pairs of hours the part of work = 5 ×

3/{16}

{15}/{16}

will be completed
Remaining work = 1 -

{15}/{16}

1/{16}

which will be done by A.
Time taken by A to complete the

1/{16}

work =

{1/{16}}/{1/8}

1/2

hour.
Hence, required number of hours = 10 +

1/2

10 1/2

hours.

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