The answer is d there are no active volcanoes sending carbon dioxide back into
Answer:
25km/hr (take the word train as bus )
Step-by-step explanation:
Answer
Let x km/hr be the constant speed of the train,
Then Time taken to cover 300km=
x
300
hrs
Time taken to cover 300km when the speed is increased by 5km/hr=
x+5
300
hours
It is given that the time to cover 300km is reduced by 2 hours
∴
x
300
−
x+5
300
=2
⇒
x(x+5)
300(x+5)−300x
=2⇒2x
2
+10x=1500
⇒x
2
+5x−750=0⇒x
2
+30x−25x−750=0
⇒(x+30)(x−25)=0⇒x=25orx=−30
But x cannot be negative. Therefore x=25
Hence, the original speed of the train is 25km/hr
So this is a Pythagorean problem where
A^2+b^2=c^2
a is 2
X is b
5 is c
Plug that into the equation and get
4+b^2=25
B^2=21
B=sqrt(21)=4.6kilometer
Answer:
D= 10
Step-by-step explanation:
3=(1.10)^t
Log(3)=t*log(1.10)
t=log(3)÷log(1.10)
t=11.5 years
