How many kilometers per month, per country ?

Question

the british tunnelled for 2.5 months before the french and averaged 0.63 kilometers a month, the french averaged 0.47 a month. total was 37.9 kilometers how many kilometers of tunnel did each country build ?

Answer 1

british tunneled for T+2.5 months and french tunneled for  T months

I presume that both the sides met in one place

Distance tunneled by British = (T+2.5) * 0.63

and by French = T*0.47

Total was 37.9

therefore 0.63 T + 1.575 + 0.47 T = 37.9

therefore 1.1T = 36.325

therefrore T = 33.02 months

British tunneled distance = (33.02 + 2.5) * 0.63 = 22.38 kms

french was 33.02 * 0.47 = 15.52 kms

AM