Question

John and David work on alternate days with John starting on the first day. John does 12.5% of the total work on the last day and finishes the work. If John alone can do the work in 6 days then which of following can be the number of days in which David alone can do the whole work? a) 24 days (b) 12 days (c) 8 days (d) 10 days

Answer 1

Answer:

The answer is 8 days

Step-by-step explanation:

We can solve this by two methods

here i will explain both methods

1. option method

let David can do it in 8 days

then

john. = 6 days

David. = 8 days

total work is 24 ( assume)

in a day work

john = 4

David = 3

one day john + one day john

4 + 3 = 7

7×3= 21

rest work is 24-21=3

which is. 3×100/24 = 12.5%

which is done by john

and this 12.5% is proving our answer.

2. Trick method

the work which was done by john on last day was 12.5%

John's one day work is

$16 \times \frac{1}{4}$

and he did only 12.5 % that means this is David's one day work share

so David's days

100/12.5= 8 days