120 minutes
Step by step:
divide 20 by 2.5 to find how many minutes it takes to drive 1 mile, then multiply that by 15 miles
Let Lisa's height be x, Ian's be y and Jim's be z
x = 10 + y . . . (1)
y = 14 + z . . . (2)
y + 14 + z + 14 = 170 + x + 14
y + z - x = 170 + 14 - 28 = 156 . . . (3)
From (2), z = y - 14 . . . (4)
Putting (1) and (4) into (3) gives,
y + y - 14 - 10 - y = 156
y = 156 + 24 = 180
Therefore, Ian's height is 180 centimeters
Answer:
x = 5m/s
Step-by-step explanation:
Distance flying out = 12 km (headwind)
Distance flying back = 12 km (tailwind)
total distance = 12 + 12 =24 km
wind speed = 1km/h
speed going out (with headwind) = (x - 1) km/h
speed coming back (with tailwind) = (x + 1) km/h
Time taken to go out = distance going out / speed going out
= 12 / (x-1)
Time taken to come back = distance coming back / speed coming back
= 12 / (x+1)
total time = time taken to go out + time taken to come back
5 =[ 12/(x-1) ] + [ 12/(x-1)]
expanding this, we will get
5x² - 24x - 5 = 0
solving quadratic equation, we will get
x = -1/5 (impossible because speed cannot be negative)
or
x = 5 (answer)
The answer should be B) an=3+5(n-1)
hope i helped :)
