15 mi/h= 15mi/60 min= 1/4 (mi/min)
x is original speed (mi/min)
t is original time
x*t =260
(x+1/4)=5x/4 is new speed
t-20 - new time
(x+1/4)(t-20)=260
xt = (x+1/4)(t-20)
xt=xt + t/4 - 20x - 5
t/4=20x+5
t=80x +20
We can substitute t=80x +20 into equation x*t =260
x*(80x+20)=260
80x²+20x-260=0
4x²+x-13=0
D=b² - 4ac = 1+4*4*13= 209
x=(-1+/-√209)/2*4
x=1.68 mi/min
1.68mi/min * 60 min/1h≈100 mi/h
Check
260/100=2.6h time with old speed
260/(115)=2.26 h time with new speed
2.6-2.26 = 0.34 h difference between old and new time
0.34h*60min/1h≈20 min difference between old and new time in minutes
Answer:
Step-by-step explanation:
b nb v hjm,vkg
Practice is key in mathematics! Always search up the topic and re-read the lessons with some practice problems to see if you got it. Asking your teacher and peers to help is another way to go.
Remember, your teacher had to learn this in order to teach you about it!
Answer:
Step-by-step explanation:
H0 : μ ≥ 6
H1 : μ < 6
Test statistic :
n = 20
Sample Mean, x = 3
σ = 1.5
Test statistic = (x - μ) ÷ σ/sqrt(n)
Test statistic = (3 - 6) ÷ 1.5/sqrt(20)
Test statistic = - 3 / 0.3354101
Test statistic = −8.944271
Since, sample size is < 30 ;
Obtaining the Critical value using the from T;
Tcritical at 0.05, df = 19 = - 1.729
Tstatistic < Tcritical
−8.944271 < - 1.729
Hence, we reject the Null:
We can conclude that there is significant evidence that the number of complaints received by Lara music store is different from number of complaints received by music stores in general.
