Question

2 men and 3 boys can complete a work in 10 days, while 3 men and 2 boys can complete in 8 days. in how many days can 2 men and 1 boy complete the same work?

Answer 1

Hi,

Let's assume a the part of the work that a man can do in 1 day.

Let's assume b the part of the work that a boy can do in 1 day.

(En France, il est interdit de faire travailler les enfants).

1=(2*a+3*b)*10 ==>2a+3b=1/10 (1)

1=(3*a+2*b)*8==>3a+2b=1/8 (2)

(1)*3-(2)*2==> 5b=1/20==>b=1/100

2a=1/10-3*1/100==>b=7/200

(a*2+b*1)*x=1

==> (2*7/200+1/100)*x=1

==>8/100*x=1

==>x=100/8

==>x=12.5 days