Math: A new car dealership sells cars and trucks in a ratio of 7 to 5. Last month, the dealership sold 84 cars and trucks. how many cars and how many trucks were sold? please try to show me work
2007-12-09 11:07:18 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
7 cars to 5 trucks just means that 7/12 of vehicles sold are cars. 5/12 are trucks
84 x 7/12 = 49 cars
84 x 5/12 = 35 trucks
2007-12-09 11:15:19 · answer #1 · answered by SoulDawg 4 UGA 6 · 0⤊ 0⤋
let the number of:
cars = c
trucks = t
Then last month, c + t = 84 (eqn 1)
Also from the ratio we know that ratio of cars to trucks is 7:5, or mathematically, this is saying:
c/t = 7/5
(c/t) * t = (7/5) * t
c = (7/5) * t
substituting for 'c' back in eqn 1,
c + t = 84
<=> (7/5)*t + t = 84
<=> (7/5)*t + (5/5)*t = 84
<=> 7t/5 + 5t/5 = 84
taking 5 as the common denominator,
<=> (7t + 5t)/5 = 84
<=> (12t)/5 = 84
<=> (12t)/5 *5 = 84* 5
<=> 12t = 420
<=> t = 420/12 = 35
and c = (7/5) * t = (7/5) * 35 = 49
So 49 cars and 35 trucks were sold last month!
2007-12-09 19:16:39 · answer #2 · answered by Kartik G 2 · 0⤊ 0⤋
7+5=12
84/12=7
7x7=49 cars
5x7=35 trucks
2007-12-09 19:19:57 · answer #3 · answered by xeno'sdaughter 5 · 1⤊ 0⤋
total units is 7+5=12
total number of vehicles =84
each unit is 84/12=7vehicle
trucks is 5 units=5x7=35 trucks and cars =40 cars
2007-12-09 19:11:41 · answer #4 · answered by someone else 7 · 0⤊ 1⤋
this could be wrong but you have two factors
7x + 5y=84
you could graph this after isolating y by itself on one side of the equation and removing the number so,
5y=-7x+84
y=-7/5x + 84/5
2007-12-09 19:12:59 · answer #5 · answered by Anonymous · 0⤊ 0⤋