Begging for help algebra word problem..due tomorrow?

Question

A car travels 120km at a certain speed. If the speed had been 10kmh faster, the trip could have been made in 2h less time. Find the speed.

Answer 1

120/x-120/(x+10)=2 multiply by x(x+10)
120(x+10)-120x=2x(x+10)
120x+1200-120x=2x^2+20x
2x^2+20x-1200=0
x^2+10x-600=0
(x+30)(x-20)=0
x+30=0
x=-30
or
x-20=0
x=20.
x<0 has no physical meaning, so x=20.

check
at 20kph, 120km takes 120/20=6hrs
at 20+10=30kph, 120km takes 120/30=4hrs. 2 hrs faster.

Answer 2

The answer is 20 km/hr

start with the equation (120/t) = (120/(t-2)) - 10
multipy by (t)(t-2) to get the equation
120(t-2) = 120(t) - 10(t)(t-2)
0 = -10t^2 +20t +240
which can be solved quadratically to produce
t = 6 or t = -4, so t = 6 and v = 120/6 = 20 km/hr
You can check the answer by testing that
120/6 = (120/4) - 10
20 = 30 - 10

Answer 3

120/speed = time
120/(speed+10) = time -2

you want to rearrange to find speed without having time in the final equation.
Best of Luck - Mike

Answer 4

Invesment on 7% = $x invesment on 5% =$(3300-x) interest from the two x*(0.07)+(3300-x)(0.05) =205 Multiply the two edge by ability of one hundred 7x +sixteen,500 -5x =20500 2x =20,500-sixteen,500 =4,000 x =$2,000 Balace = 3,3 hundred -2,000 =$a million,3 hundred consequently An investor invested a entire of $3,3 hundred in 2 mutual funds. One fund earned a 7% earnings on an identical time as the different earned a 5% earnings. If the investor's entire earnings became $205, how plenty became invested in each and every mutual fund? the quantity invested interior the mutual fund became that earned 7% became=$2,000 the quantity invested interior the mutual fund became that earned 5% became= $a million,3 hundred

Answer 5

divide 20kph into 120km you get 6 hours. now add 10kph to 20kph and get 30kph. Divide 30 into 120 and you get 4 hours.
The speeds are 20kph & 30kph. The 10kph X 2 hours gave me the 20kph.

Answer 6

Let s = speed, time =t

120/speed = time
120/(speed+10) = time -2

so 120/s = t
120(s+10) = t -2

from these two equations, we get s = 20, t = 6

Answer 7

do your own homework!