Well, 0.90 is actually equal to 0.9. It is less than 0.91 and equal to 0.9 so that means it is not correct.
I hope this helps:)
Answer: 16 litres
Step-by-step explanation:
A: 1l x km
B: 1l x+5 km
Running 400 km A used 400/x litres
Running 400 km B used 400/(x+5) litres
400/x- 400/(x+5)= 4
400*(x+5)- x*400-4*x*(x+5)=0
400*x+2000-400*x-4*x²-20*x=0
2000-4*x²-20*x=0 difide by 4 both sides of equation
500-x²-5*x=0
Lets solve the equation using discriminant:
D=5²-(-1)*4*500=2025
sqrt(D)=45
x1= (5+45)/(-2)= -25 x2=(5-45)/(-2)=20
x1=-25 x2=20
x1<0 so is not the solution of the problem ( number of litres can't be negative)
So A uses litr per x=20 km and B uses 1 litr per 20+5=25 km
Running 400 km B uses 400/25=16 litres
Distance=speed times time
if they take the same time, we cal the time , t
b=bike speed
w=walking speed
bikedistnace=17=bt
walkdistance=9=wt
b is 4 more than w
b=4+w
we have
17=bt
9=wt
b=4w
ok so
multiply first equation by 9 and 2nd by 17
153=9bt
153=17wt
set equal
9bt=17wt
divide both sides by t
9b=17w
sub b=4+w for b
9(4+w)=17w
distribute
36+9w=17w
minus 9w both sides
36=8w
divide both sides by 8
4.5=w
he walks 4.5kph
Integers involve with negative, so D isn't the correct answer the correct answer will be A.
