Question

A and b can do a piece of work in 30 days, while b and c can do the same work in 24 days and c and a in 20 days. they all work together for 10 days when b and c leave. how many days more will a take to finish the work?

a. 18 days

b. 28 days

c. 30 days

d. 36 days

Answer 1

solution

a+b =30
b+c =24
c+a =20

first we have to find the values of the following:-
so, we would have to do it in conditional way

like

##you would have to do it vertically, i did it like this because i have no other way ##
'a' would be
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20...
(then 'b' would be)
29 28 27 26 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10...
because they add upto 30 and a+b =30
we will consider the value in between b's value 23 and a's value 19 because b+c =24 so b can't be more than 23 and c+a =20 so a can't
be more 19
so according to this c's conditions will depend as b+c =24

then c would be
we will write in new column beside a and b column
its values will start on the right of b's 23
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 .....
# so the conditional values will be
a / b / c
7 23 1
8 22 2
9 21 3
10 20 4
11 19 5
12 18 6
****13 17 7******
14 16 8
15 15 9
16 14 10
17 13 12
18 12 13
19 11 14
20 10 15

as these values fit in the equation
so,a= 13
b= 17
c= 7

then according to the question,
a,b,c worked for 10 days
then how many more days would be needed to a to finish the job

total days they can work = 13+17+7 => 37
no. of days they have worked = 10
no. of days left to finish the job = 37-10 = 27
$$ the ans. is 27days $$

##hey buddy can you check out the options that you gave i guess they are not correct because i have solved the question in front of you##



you've got to mark me as brainliest, i've been writing this answer from about an hour to explain it to you
since the app's photo inserting feature isn't working i had to type all this !!!