M4maths Previous Puzzles

12 Jan 2016 Time and work

8 teachers and 10 children do a school work in the same days as 4 teachers and 16 children do. 1 teacher and 3 children start a school work to finish it in 40 days. After eighteen days, 9/20th part of the school work had been finished. How many children should be increased to make the school work complete in exact time.

OPtion

1) 9
2) 6
3) 3
4) 0
5) 4
6) 5
7) 1
8) 7
9) 8
10) 2

Solution

In 18 days, (9/20)th part of school work is finished
Thus in 1 day, {9/(20*18)}th = 1/40th part of school work is finished
Hence in 40 days, school work will be complete.
No additional children are required.

Option 4)

Correct Option: 4 Best Solution (16)

harsh dhir   9 years AGO

18/40=9/20.
Since 9/20 part is finished in the given time,which is equal,so there are no more children required.

Like? Yes (2) | No   

Shagun Chaudhary   9 years AGO

(1÷8x)+(1÷10y)=(1÷4x)+(1÷16y)
=> x=10(y/3)
18{(1/x)+(1/3y)}=(9/20)
=>x=760/9
=>y=76/3
40{(1/x)+(1/(n+3)y)}=1
===>n=0

Like? Yes (2) | No   

DEBMALYA GHOSAL   9 years AGO

let total work 120.
8t+10c=4t+16c => 2t=3c
then 1t+3c=3t

3t's efficiency=3
so remaining work=120-(3*18)=66
remaining days=40-18=22
we know, M1*D1/W1=M2*D2/W2
so, 40*3/120=x*22/66
x=3
that means no more children should be increased.
answer 4) 0

Like? Yes (1) | No   

luciya   9 years AGO

18 days = 9/20 work
40 days= 1 i.e. work completed

No increase in the no. of children would be required

Like? Yes (1) | No   

Dr.Dipin Singh   9 years AGO

in 1 day , 1/40 work should be finished.
In 18 days, 18/40 or 9/20 work should be finished.
In 18 days, 9/20 work ( as required) is finished.
so no additional children are required to finish work in 40 days.

Like? Yes (1) | No   

N.Vennela Rani   9 years AGO

answer is zero bcz children are sufficient to comlete work in exact time

Like? Yes (1) | No   

payal kumari   9 years AGO

8T+10C=X Days
4T+16C=X Days
then,3C=2T
1T+3C=40Days
1T+2T=40 Days
3T=40 Days
920w=18 days
remaining work and remaining time taken is22
1120
2240=1120
so work is completed within time
no need to add childrens
ans=0

Like? Yes (1) | No   

JANARTHANAN RAM   9 years AGO

8T+10C=4T+16C;
T=1.5C;
Assume that Total work is 80 Units,
1T +3C=3T;
3 Teacher plan Complete work in 40days.
So they do 2 units per day;
After 18 days 36 units should be completed,it is also same as 9/20*80=36;
So no need to add children.

Like? Yes (1) | No   

shailesh kumar shashi   9 years AGO

1 teacher and 3children do 9/20 of work in 18 days
In 1 day they can do = (9/20)/18=1/40
therefore, they can finish the in 40 days
hence, no more children required
ans is 0.

Like? Yes (1) | No   

swetha rangaraj   9 years AGO

18d=9/20 so for 1d=0.5/20 parts
so after 40 days (0.5*40)/20=20/20
so no need to increase

Like? Yes (1) | No   

Sai Manish   9 years AGO

As in 18 days 45 percent of work done, in remaining days with same children 55 percent of work will be done .

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Param   9 years AGO

8T+10C=4T+16C
2T=3C
T+3C=40D
9C=80D
18 days >>9/20 done which is double from 9C=80D, so work will be finished on time without any adding of children.

Like? Yes (1) | No   

Sreehari   9 years AGO

2 children is equal to 1 teacher.
So 3 teachers can do the work (100%) in 40 days
Work done by 3 teachers in 18 days is 45% i.e.. 9/20.
So no more children are required.

Like? Yes (1) | No   

Jamil Ahmed   9 years AGO

Since 9/20th part of the work has been finished in 18 days by 1 teacher & 3 children, the part of work which shall be done by them in remaining 22 days = 22*(9/20)/18 = 11/20th part of the whole work.

So, the total work done by 1 teacher and 3 children in 40 days = 9/20 + 11/20 = 1 i.e. whole work will be completed by 1 teacher and 3 children in exact time.

Therefore, no. of children reqd. to be increased = 0.

Like? Yes (1) | No   

MALAY SAHA   9 years AGO

work will be completed within time with the ongoing pace.

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richa   9 years AGO

in 18 days 9/20means in one day 1/40 , remaining work 11/20 ,in 22 days 11/20 means in one day 1/40

Like? Yes (1) | No