Time and Work-Basic test 1

Answer: Option C

Explanation

Let A take a and B take 3a days to finish the work.

As per the question,

3a-a=30

 $\therefore \mathrm{x}=\frac{30}{2}=15 \mathrm{days}$

Time taken by B to complete the work is 3a

So 3×15=45 days

Therefore 1 day work of (A+B)= $\frac{1}{15}+\frac{1}{45}=\frac{3+1}{45}=\frac{4}{45}$

Hence, (A+B) will finish the work in $\frac{45}{4} \mathrm{or} 11\frac{1}{4}\mathrm{days}$

Hence option C is correct

Answer: Option A

Explanation

According to the formula, if a person can do $\frac{1}{x}$th work in 1 days, then he can complete the work in  x days .

Similarly here, Susmitha can do $\frac{1}{25}$ of a task 1 day.

So, she can complete the task in 25 days

Hence option A is correct

Answer: Option B

Explanation

According to the formula, if a person can do $\frac{1}{x}$^th work in 1 days, then his efficency in percentage is $\frac{100}{\mathrm{x}}\%$.

Similarly here, Ravi can complete $\frac{1}{5}$^th of an assignment in 1 day.

So, his efficiency in percentage is $\frac{100}{5}=20\%$

Hence option B is correct

Answer: Option C

Explanation

We know that Time and Work are directly proportional to each other. In other words More work requires more Time.

Here, Rita completes a job in 40 days.

So, 3 similar jobs require 40×3=120 days

Hence option C is correct

Answer: Option C

Explanation

According to the above given formula, If M₁ persons can do W₁ work in D₁ days working T₁ hours a day and M₂ persons can do W₂ work in D₂ days working T₂ hours a day then,

M₁D₁W₁= M₂D₂W₂

Here W₁=W₂

$$\begin{gathered} 16\times 10\times 1= 8\times {\mathrm{M}}_2\times 1 \\ {\mathrm{M}}_2=\frac{16\times 10 \times 1}{8 \times 1} =\frac{160}{8}=20 \end{gathered}$$

Hence, 20 men can complete the same work in 8 days

Hence option C is correct