Question

12 persons take 10 days to build a 3 km road.How many days will 15 persons take to build 6 km road ?​

Answer 1

Step-by-step explanation:

Let total work be W, and work done by 1 man in 1 day be w, then

5×w×12=W

Also,

x×w×10=W ( where x is number of men required to build the wall in 10 days)

Equating both equations, we get,

x×w×10=5×w×12

⇒x=

10

60

=6men

Answer 2

According to the given in the question:

12 persons take 10 days to build a 3 km road.

Divide by 12:

1 person takes 10 days to build a $\frac{1}{4}$ km road.

So, 15 (1 x 15) persons take $\frac{2}{3}$ (10 ÷ 15) days  to build a $\frac{1}{4}$ km road.

Multiply by 24:

15 persons take 16 days to build 6 km road.