Respuesta :
a) If 25 miles =1 gallon
Then 12000=12000/25=480 gallons
If 1 gallon =$2.6
Then 480 gallons = 480 x 2.6
= 1248.00
b) If (25 + x)miles =1 gallon
Then 12000miles=1200/(25+x)
gallons
c) (31200/(25+x)) - (1248/(25+x)
=(31200-1248(25+x)) / (25+x)
=1248((25- (25+x))/(25+x)
=1248x/(25+x)
d) 1248x/(25+x)=400. Cross
multiply
1248x =10000+400x. Group like
terms
848x/848=10000/848
x=11.79
=(25+x)=(25+11.79)
=36.79 miles per gallon
Then 12000=12000/25=480 gallons
If 1 gallon =$2.6
Then 480 gallons = 480 x 2.6
= 1248.00
b) If (25 + x)miles =1 gallon
Then 12000miles=1200/(25+x)
gallons
c) (31200/(25+x)) - (1248/(25+x)
=(31200-1248(25+x)) / (25+x)
=1248((25- (25+x))/(25+x)
=1248x/(25+x)
d) 1248x/(25+x)=400. Cross
multiply
1248x =10000+400x. Group like
terms
848x/848=10000/848
x=11.79
=(25+x)=(25+11.79)
=36.79 miles per gallon
a)The cost of 480 gallons = $1248
b)Expression to represent the new yearly cost of gasoline = $ 31200/ (25+x)
c)total savings on gasoline per year =$1248x/ 25+ x
d)miles per gallon does the new car get = 36.79 miles
What is unitary method?
Unitary method Technique to solve a problem by first finding the value of a single unit , and then finding the necessary value by multiplying the single unit value.
Given :
drive an average of = 12000miles per year
one gallon consumed = after every 25 miles
cost per gallon of gasoline = $ 2.60
a) 25 miles consume = 1 gallon of gasoline
12000 mile will consume = (1/ 25)* 12000 =480 gallons
cost of one gallon = $ 2.60
cost of 480 gallons = $ 2.60 * 480= $1248
b) another car gives x more miles per gallon :
25 + x miles consume = 1 gallon
12000 miles will consume = 1/ (25+x) * 12000 gallons
cost of one gallon = $ 2.60
cost of 1/ (25+x) * 12000 gallons= 2.60 * (1/ (25+x) * 12000)
= $ 31200/ 25+x
c)Total savings will be = cost spent in initial case - cost in 2nd case
= 1248 - 31200/(25+x)
= (31200 + 1248 x - 31200)/ (25+x)
= $1248x/ 25+ x equation 1
d) let saving = $ 400 (given ) equation 2
savings calculated in previous part =$1288x/ 25+ x
equating both the equations 1 and 2
1248x/ 25+x = 400
1248x = 10000 + 400x
1248x -400x = 10000
x = 11 .79 miles
Total miles covered per gallon = 25 + x = 25 + 11.79 = 36.79 miles
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