Question 1
In a class test, the marks scored by 11 students are 15,19,22,7,5,21,9,8,13,17,23. Find
(i) Median
a) 15 b) 19 c) 5 d) 9
Ans a)
(ii) Lower quartile
a) 9 b) 8 c) 17 d) 23
Ans b)
(iii) Upper quartile
a) 22 b) 21 c) 23 d) 15
Ans b)
(iv) Inter quartile range
a) 15) b) 8 c) 21 d) 13
Ans d)
Rationale
On arranging the given variates (marks) in ascending order , we get
5, 7, 8 , 9, 13, 15, 17, 19,21, 22, 23
(i) Here , n ( no of observations)=11, which is odd
Median= n+1/2th observation= 6th observation =15
(ii) Lower quartile(Q1)= n+1/4 th observation=3rd observation=8
(iii) Upper quartile(Q3)=3(n+1)/4 th observation=9th observation=21
(iv) Inter quartile range= Q3-Q1=21-8=13
Question 2
A woman walks 200 m in 6 min.
(I) Find her speed in km/h.
a) 4km/hr b)2km/hr c) 6km/hr d) 8 km/hr
Ans b)
(ii) What distance would she cover in 4 hr 30 min?
a) 18 km b)10 km c)9 km d) 15 km
Ans c)
(iii) How long would she take to cover 7 km?
a) 3.5 hr b) 1.5 hr c) 2.5 hr d) 4.5 hr
Ans a)
Rationale
(I) Speed=Distance/time=200m/6 min= 200/6*60 m/s= 5/9 m/s= 5/9* 18/5 km/h=2 km/hr
(ii) The distance she would cover in 4 hr 30min (i.e. 9/2h)
=Speed*time=(2km/hr)*(9/2h)= 9 km.
(iii) The time he would take to cover 7 km
Distance/speed=7/2=3.5hr
