please ans the question no 5.

Answer:

(i)Together in 10 days

(ii) They can finish the work individually as:

a=30 days

b=60 days

c=20 days

Step-by-step explanation:

one day work of a and b =a+b=1/20

one day work of b and c =b+c=1/15

one day work of c and a =c+a=1/12

adding we get

a+b+b+c+c+a=1/20+1/15+1/12

2(a+b+c)=1/60(3+4+5)=12/60=1/5

a+b+c=1/10

one day work of a and b and c=1/10

so the will complete the work together in 10 days

Now a=(a+b+c)-(b+c)=1/10-1/15=3-2/30=1/30

b=(a+b+c)-(a+c)=1/10-1/12=6-5/60=1/60

c=(a+b+c)-(a+b)=1/10-1/20=1/20

hence they can finish the work individually as:

a=30 days

b=60 days

c=20 days