2005 - JAMB Mathematics Past Questions and Answers - page 5
41
In how many ways can 6coloured chalks be arranged if 2 are same colour?
A
60
B
120
C
240
D
360
correct option: d
\(\frac{6!}{2!}=ways=\frac{6\times5\times4\times3\times2!}{2!}\=6\times5\times4\times3\=360\hspace{1mm}ways\)
Users' Answers & Comments42
How many possible ways are there of seating seven people P,Q,R,S,T,U and V at a circular table
A
360
B
720
C
2520
D
5040
43
A box contains 5 blue balls, 3 red balls and 2 white balls. Two balls are selected from the box with replacement. Find the probability of obtaining two blue or two red balls
A
17/50
B
3/25
C
1/50
D
3/250
correct option: a
Blue balls = 5
Red balls = 3
White balls = 2
Total = 10
P(Two blue) = 5/10 * 5/10 = 25/100
P(Two Red) = 3/10 * 3/10 = 9/100
∴P(Two blue or two red balls)
= 25/100 + 9/100
= 34/100
= 17/50
Users' Answers & CommentsRed balls = 3
White balls = 2
Total = 10
P(Two blue) = 5/10 * 5/10 = 25/100
P(Two Red) = 3/10 * 3/10 = 9/100
∴P(Two blue or two red balls)
= 25/100 + 9/100
= 34/100
= 17/50
44
What is the probability that an integer x,(1 \(\leq\) x \(\leq\) 20) chosen at random is divisible by both 2 and 3?
A
1/20
B
1/3
C
3/20
D
7/10
correct option: c
U = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20}
A = {x/x is divisible by 2}
A = {2,4,6,8,10,12,14,16,18,20}
B = {x/x is divisible by 3}
A ∩ B = {6, 12, 18}
P(Number divisible by both 2 and 3)
= 3/20
Users' Answers & CommentsA = {x/x is divisible by 2}
A = {2,4,6,8,10,12,14,16,18,20}
B = {x/x is divisible by 3}
A ∩ B = {6, 12, 18}
P(Number divisible by both 2 and 3)
= 3/20
45
A
19
B
6
C
15
D
4
46
A
x \(\geq\) 2
B
0 \(\geq\) x \(\geq\) 2
C
-2 \(\geq\) x \(\geq\) 0, x \(\leq\) 2
D
x \(\geq\) -2, 0 \(\geq\) x \(\geq\) 2
correct option: c
Users' Answers & Comments47
A
60o
B
100o
C
120o
D
140o
correct option: c
Users' Answers & Comments48
A
20o
B
25o
C
50o
D
80o
correct option: b
< OUT = < OTU
< OUT = \(\frac{180^o - 70^o}{2} = \frac{110^o}{2} = 55^o\)
< RUT = 180o - 100o = 80o
< RUO = < RUT - < OUT
= 80o - 55o
= 25o
Users' Answers & Comments< OUT = \(\frac{180^o - 70^o}{2} = \frac{110^o}{2} = 55^o\)
< RUT = 180o - 100o = 80o
< RUO = < RUT - < OUT
= 80o - 55o
= 25o
49
A
226o
B
224o
C
136o
D
134o
50
A
16
B
12
C
8
D
6