Answer:
Step-by-step explanation:
let the speed of one plane=x
speed of other plane=x+80
time=4 hrs
then 4x+4(x+80)=3800
4x+4x+320=3800
8x=3800-320
or 8x=3480
x=435
speed of one plane=435 m/h
speed of other plane=435+80=515 m/h
2.
Let he walks x hrs
then he take a taxi for 2-x hrs
4x+(2-x)50=31
4x+100-50x=31
-46x=-69

so he walks 3/2 hrs=1.5 hrs
travels by taxi=2-1.5=0.5 hrs
distance traveled by taxi=0.5×50=25 miles
Answer:
5 2/10
Step-by-step explanation:
Answer:
600 numbers
Step-by-step explanation:
For six-digit numbers, we need to use all digits 8,0,1,3,7,5 each once.
However, 0 cannot be used as the first digit, because it would make a 5-digit number.
Therefore
there are 5 choices for the first digit (exclude 0)
there are 5 choices for the first digit (include 0)
there are 4 choices for the first digit
there are 3 choices for the first digit
there are 2 choices for the first digit
there are 1 choices for the first digit
for a total of 5*5*4*3*2*1 = 600 numbers
The amount of heat released when 12.0g of helium gas condense at 2.17 K is; -250 J
The latent heat of vapourization of a substance is the amount of heat required to effect a change of state of the substance from liquid to gaseous state.
However, since we are required to determine heat released when the helium gas condenses.
The heat of condensation per gram is; -21 J/g.
Therefore, for 12grams, the heat of condensation released is; 12 × -21 = -252 J.
Approximately, -250J.
Read more on latent heat:
brainly.com/question/19863536