A built a tunnel at .63 km per month and started 2.5 months before B who built at .47 km per month. After meeting at 37.9 km how many did each build?

Question

A tunneled .63 km per month and started 2.5 months before B who tunneled the other way .47 km per month.  They met at 37.9 km tunneled.  How far did each tunnel?

Answer 1

Let's Consider

 

 months tunneling by the A =t
So
 months tunneling by the B =t-2.5

distance equation:

 

Dist = speed * time

 

Distance of A = 0.63* t=0.63t

 

Distance of B=0.47(t-2.5)=0.47t  - 1.175

A distance +B distance = 37.9

0.63t + 0.47t - 1.175 = 37.9

0.63t + 0.47t = 37.9 + 1.175

 

1.1t = 39.075

t = 35.52 months

 

Time taken by A =t= 35.52 months

 

Time taken by B=t-2.5=35.52-2.5=33.02 months

 

then

Distance build by A

Distance = speed * time
Distance =0.63 * 35.52 = 22.38 km Built by the A

And

 

Distance build by B
Distance = speed * time
Distance =0.47 * 33.02
Distance =0 .47 * 33.02= 15.52 km built by the B