algebra 1 needs help within 5 min

Question

When building the Channel, the English and French each started drilling on opposite sides of the English Channel. The two sections became one in 1990. The French used more advanced drilling machinery than the English. Suppose the English could drill the Channel in 6.2 years, and the French could drill in 5.8 years, how long would it have taken the two together?

Answer 1

6.2 = 62/10 = 31/5

 

5.8 = 58/10 = 29/5

 

1/6.2 + 1/5.8 =

 

5/31 + 5/29 = (5*29 +5*31)/(31*29)

 

                   = 300/899

 

 

300/899 of the job completed in 1 year.

 

It will take them 899/300 = 2 and 299/300 years

or almost 3 years working together