Total people x,
then, 3.5x + 5.5x + 6 = 51
simplify, 9x +6 = 51
subtract 6 on both sides, 9x= 45
divide by 9 on both sides, x= 5
therefore, total 5 people in the family.
Answer:
Step-by-step explanation:

Combine like terms. 1/4 and 7/8 are like terms and LCD of 4 and 8 is 8
9/10y and -3/5y are like terms and LCD of 10 , 5 is 10

x = total amount split between Adam and Tom.
since we know the total amount split between both in a 18 : 17 ratio is "x", let's divide "x" by (18 + 17) and distribute accordingly to get the amount of each.
![\stackrel{Adam~received}{18\cdot \cfrac{x}{18+17}}\qquad \qquad \stackrel{Tom~received}{17\cdot \cfrac{x}{18+17}} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{since we know that Adam got "5" more}}{ \stackrel{Adam}{18\cdot \cfrac{x}{18+17}}~~ = ~~\stackrel{Tom}{17\cdot \cfrac{x}{18+17}~~ + ~~5} }\qquad \implies \qquad \cfrac{18x}{35}~~ + ~~\cfrac{17x}{35}+5](https://tex.z-dn.net/?f=%5Cstackrel%7BAdam~received%7D%7B18%5Ccdot%20%5Ccfrac%7Bx%7D%7B18%2B17%7D%7D%5Cqquad%20%5Cqquad%20%5Cstackrel%7BTom~received%7D%7B17%5Ccdot%20%5Ccfrac%7Bx%7D%7B18%2B17%7D%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7Bsince%20we%20know%20that%20Adam%20got%20%225%22%20more%7D%7D%7B%20%5Cstackrel%7BAdam%7D%7B18%5Ccdot%20%5Ccfrac%7Bx%7D%7B18%2B17%7D%7D~~%20%3D%20~~%5Cstackrel%7BTom%7D%7B17%5Ccdot%20%5Ccfrac%7Bx%7D%7B18%2B17%7D~~%20%2B%20~~5%7D%20%7D%5Cqquad%20%5Cimplies%20%5Cqquad%20%5Ccfrac%7B18x%7D%7B35%7D~~%20%2B%20~~%5Ccfrac%7B17x%7D%7B35%7D%2B5)
![\stackrel{\textit{multiplying both sides by }\stackrel{LCD}{35}}{35\left( \cfrac{18x}{35} \right)~~ = ~~35\left( \cfrac{17x}{35}+5 \right)}\implies 18x~~ = ~~17x+175\implies \boxed{x =175} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{Tom~received}{17\cdot \cfrac{x}{18+17}}\implies \cfrac{17(175)}{35}\implies \blacktriangleright 85 \blacktriangleleft](https://tex.z-dn.net/?f=%5Cstackrel%7B%5Ctextit%7Bmultiplying%20both%20sides%20by%20%7D%5Cstackrel%7BLCD%7D%7B35%7D%7D%7B35%5Cleft%28%20%5Ccfrac%7B18x%7D%7B35%7D%20%5Cright%29~~%20%3D%20~~35%5Cleft%28%20%5Ccfrac%7B17x%7D%7B35%7D%2B5%20%5Cright%29%7D%5Cimplies%2018x~~%20%3D%20~~17x%2B175%5Cimplies%20%5Cboxed%7Bx%20%3D175%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7BTom~received%7D%7B17%5Ccdot%20%5Ccfrac%7Bx%7D%7B18%2B17%7D%7D%5Cimplies%20%5Ccfrac%7B17%28175%29%7D%7B35%7D%5Cimplies%20%5Cblacktriangleright%2085%20%5Cblacktriangleleft)
A)
145 - 5d
5d = 145, set equal
29 days to lay all the track
b)
5*19 = 95
145-95 = 50
After 19 days, they have 50 miles to go.
Answer:y = 9x
Step-by-step explanation: