Answer:
7.92 m.
Step-by-step explanation:
Mean height = ∑(f . x) / ∑f where x is the midpoint and f the frequencies
The midpoints for the heights are:
2 for frequency 8 ( 0 + 4)/ 2 = 2
6 for .. 21
10 for .. 12
14 for .. 7
18 for .. 2
So the mean is:
[(2*8) + (6*21) + (10*12) + (14*7) + (18*2) ] / (8 + 21+12+7+2)
= 396 / 50
= 7.92 m.
Answer:
3.7 miles per day
Step-by-step explanation:
6/7 because 48 divided by 8 is 6 and 56 divided by 8 is 7
3 + 2k
This is because multiplying by 1/5 is like dividing each term by 5
X = velocity of plane
y = velocity of wind
x - y = 1680/5 = 336 mph .....(1) [ plane flying against the wind]
&
x + y = 1680/4 = 420 mph....(2) [ plane flying with the wind]
Adding (1) and (2) to eliminate y gives
2x = 756
x = 378 mph is the speed of the plane with no wind.
