Question

Question
Choose the correct option.
Neena can finish a project in 30 days. Bina and Cia can do the same work in
15 and 20 days respectively. Bina and Cia start working (without Neena)
but quit after 5 days. How many days will Neena take to do the remaining
work?
N-zod
A)
12
B 3
| is d
B)
12 1/2
С C
20.
C)
13
D)
13 1/4
FACE​

Answer 1

B) 121/2 is correct answer

Answer 2

Neena can finish a project in 30 days. Bina and Cia can do the same work in 15 and 20 days respectively. Bina and Cia start working (without Neena) but quit after 5 days. How many days will Neena take to do the remaining work?

It is given that the days of work are done by three people.

Neena= 30 days.

Bina = 15 days.

Cia = 20 days.

The amount of work that can be done by three in one day is

$\frac{1}{30} + \frac{1}{15} + \frac{1}{20}$

This can be found by taking the LCM, the LCM of these three numbers is 60.

To solve these questions simple addition is used.

$\frac{2 + 4 + 3}{60} = \frac{9}{60} = \frac{3}{20}$

If Bina and Cia started working without Neena and quit after 5 days, we need to calculate the work done by Bina and CIA and the amount of work remaining.

work done by Bina and CIA in one day

$\frac{1}{15} + \frac{1}{20} = \frac{4 + 3}{60} = \frac{7}{60} = 0.116$

In 5 days the work done by them is

$0.116 \times 5 = 0.58$

The amount of work remaining is

$1 - 0.58 = 0.42$

Here, we have to calculate the no of days taken by Neena to complete the work.

In one day Neena completes.

$\frac{1}{30} of \: work$

How many days does it take to complete 0.42 of the work?

$\frac{0.42}{ \frac{1}{15} } = 0.42 \times 15 = 6.3$

The no of days required by Neena to complete the work is 6.3.

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