Question

4 Indians and 4 Chinese can do a piece of work in 3 days. While 2 Indians and 5
Chinese can finish it in 4 days. How long would it take for 1 Indian to do it? How long
would it take for 1 Chinese to do it?​

Answer 1

Answer:-

It takes no time. Because the work is already done by 2 Indians and 5 Chinese.

Its a #riddle!!!

Answer 2

Answer:

1 Indian can do the work in 18 days while 1 Chinese can do the work in 36 days.

Solution:

According to the question,

Given Data:

Step-by-step explanation:

Step 1:

Let 1 Indian can do the work in x days and 1 Chinese can do the work in y days

Indian can do in in 1 day =$\frac{1}{x}$ work

Chinese can do in 1 day = $\frac{1}{y}$work

Step 2:

Indian and Chinese together can do in 1 day = $\frac{1}{x}+ \frac{1}{y}$ work

4 Indian and 4 Chinese together can do in 1 day = $(\frac{4}{x}+ \frac{4}{y})$ work

4 Indian and 4 Chinese together can do in 3 day = 3 $(\frac{4}{x}+ \frac{4}{y})$ work

Step 3:

According to the question

$12(\frac{1}{x}+ \frac{1}{y})=1$

$=\frac{1}{x}+ \frac{1}{y}=\frac{1}{12} (1)$

Step 4:

2 Indian and 5 Chinese together can do in 1 day = $(\frac{2}{x}+ \frac{5}{y})$ work

2 Indian and 5 Chinese together can do in 4 day =$4(\frac{2}{x}+ \frac{5}{y})$work

According to the question

Step 5:

$14(\frac{2}{x}+ \frac{5}{y})=1$

$=\frac{2}{x}+ \frac{5}{y}=\frac{1}{4}$……..(2)

Step 6:

Multiplying eq (1) by 2 and subtracting it from eq (1)

$5-\frac{2}{y}=\frac{1}{4}-\frac{2}{12}$

$=\frac{3}{y}=3-\frac{2}{12}$

$=\frac{3}{y}=\frac{1}{12}$

$=y=12 \times 3$

y=36

Step 7:

Putting the value of y in eq (1)

$\frac{1}{x}+\frac{1}{36}=\frac{1}{12}$

$=\frac{1}{x}=\frac{1}{12}-\frac{1}{36}$

$=\frac{1}{x}=3-\frac{1}{36}$

Step 8:

Result

$=\frac{1}{x}=3-\frac{1}{36}$

=x=18