You could find S(9) - S(4)
a = 5 and r = 2
S(9) = 5(2^9 - 1)/(2 - 1) = 2555
S(4) = 5(2^4 - 1)/(2 - 1) = 75
The terms from 5th to 9th add to 2555 - 75 = 2480
The other alternative method is the find the 5th term and add 5 terms starting from there
T(5) = 5 x 2^(5 - 1) = 80
New sequence has a = 80 and r = 2
S(5) = 80(2^5 - 1)/(2 - 1) = 80 x 31 = 2480
Answer:
the weight of the steel beam and steel beam length
let y be weight and x be length of it
y=ax
where a is the constant
we can find it if we have two sets of values of y and x
It’s going to take 29 days to lay all the tracks because 174/6=29
