Question

A timber fence is to be built on sloping land, with the shortest piece of timber 1.2m and the longest 1.8m. there are 61 pieces of timber in the fence.  

b) what length of timber is needed for the fence altogether?

Answer 1

tn=a+(n-1)d

1.8=1.2+60d

d=.001m=1mm

this is d difference in length

sum=n/2(a+tn)
=61/2*3
=91.5m