Q.

If the mode of the following data is K, then the value of K in the data set
9, 8, 6, 7, 1, 6, 10, 6, 7, K² − 12K + 42, 9, 7 and 13 is:

(i) 6  (ii) 9  (iii) 7  (iv) 13

Choose correct option from the following:

1 (iii) and (iv)  
2 (i) and (iii)  
3 Only (i)  
4 (i) and (ii)  

Ans.

(2)

In the above dataset, value 6 and 7 have occurred most number of times, i.e., 3 times.

Also, mode = K.

So, either 6 or 7 would be the mode.

If K = 6,
K²  12K + 42 = 6²  12(6) + 42 = 6

If K = 7,
K²  12K + 42 = 7²  12(7) + 42 = 7

∴ K = 6 and K = 7

So, (i) and (iii) are correct.