Answer:
We have:
Median=Mode
Explanation:
We are given data as:
Speed(x) Frequency(y) Cumulative Frequency
12 1
13 2 1+2=3
14 6 3+6=9
15 12 9+12=21
16 6 21+6=27
17 5 27+5=32
18 1 32+1=33
19 2 33+2=35
20 4 35+4=39
21 1 N= 39+1=40
N=40
As the total number of frequency is even i.e. 40.

Hence, the median lie between the 20 and 21.
Hence,Median=15
We know that the mode is the data corresponding to highest frequency.
Hence here Mode=15 ( Since it's frequency is highest i.e. 12)
Also, Mean is calculated by:
x y xy
12 1 12
13 2 26
14 6 84
15 12 180
16 6 96
17 5 85
18 1 18
19 2 38
20 4 80
21 1 21
------------------------------------------
∑xy=640
Hence, Mean is calculated as:

Hence, Mean=16
Hence, we have:
Median=Mode=15