Question

10 students can do a job in 8 days, but on the starting day , two of them informed that they are not coming. by what fraction will the number of days required for the doing the whole work gets increased ? a.) 4/5 b.) 3/8 c.) 3/4 d.) 1/4

Answer 1

a)4/5 is right answer

Answer 2

Answer:

option d) 1/4.

Given:

10 students can do a job in 8 days,

Two of them informed that they are not coming.

To find:

What fraction will the number of days required for the doing the whole work gets increased ?

Step-by-step explanation:

It is given that,

10 students can do a job in 8 days,

So,

1 students can do work in 10 × 8 = 80 days

hence, the total work is 80 units.

And work done by 1 student in one day = $\frac{1}{80}$ units

it is also given that, two of them informed that they are not coming.

so,

remaining students are 10 - 2 = 8 students.

So, Time taken by 8 students to complete 80 units work is

= $\frac{80}{8} = 10$ days.

Earlier time taken was = 8 days

Now, time taken is = 10 days

Numbers of days increased = 10 - 8 = 2days

fraction of days increased = no. of days increased/ No. of days taken earlier

⇒ fraction of days increased = $\frac{2}{8} = \frac{1}{4}$

Hence,

number of days required for the doing the whole work gets increased  by $\frac{1}{4}$.

 

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