<em>Answer below:</em>
<em>Hope this helps :-)</em>
The answer is c.) of the 6 grade students surveyed, 12% bring their lunches to school. suppose 24 6 graders do this. how many 6 graders are at school?
Answer:
Age of Mark 
years
Age of Mark's dad 
years
Age of Mark's sister 
years
Step-by-step explanation:
Let age of Mark be 
years.
Mark's dad is three times older than Mark
Age of her Mark's dad 
Mark's sister is 2 years younger than Mark
Age of Mark's sister 
years
The sum of their ages is 48.
Age of Mark 
years
Age of Mark's dad 
years
Age of Mark's sister 
years
Answer: y = -2x + 4
Step-by-step explanation:
Answer:
- train: 40 kph
- plane: 140 kph
Step-by-step explanation:
Let t represent the speed of the train in km/h. Then 4t-20 is the speed of the plane. Travel times are the same, so we can use the formula ...
time = distance/speed
and equate the travel times.
110/t = 385/(4t-20)
Cross multiplying gives ...
110(4t -20) = 385t
440t -2200 = 385t . . . . . eliminate parentheses
55t -2200 = 0 . . . . . . . . . subtract 385t
t -40 = 0 . . . . . . . . . divide by 55
t = 40 . . . . . . . . . . . add 40; train's speed is 40 kph
4t -20 = 140 . . . . . . find plane's speed; 140 kph
The train's speed is 40 km/h; the plane's speed is 140 km/h.
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<em>Check</em>
Train's travel time = 110 km/(40 km/h) = 2.75 h.
Plane's travel time = 385 km/(140 km/h) = 2.75 h.
