JAMB Mathematics Past Questions & Answers - Page 39

192.

The goals scored by 40 football teams from three league  divisions are recorded below

No of goals 0 1 2 3 4 5 6
Frequency 4 3 15 16 1 0 1

What is the total number of goals scored by all the teams?

A.

21

B.

40

C.

91

D.

96

Correct answer is C

Let x represent number of goals \(\begin{array}{c|c|} x & F & Frequency(fx)\\\hline 0 & 4 & 0 \\\hline 1 & 3 & 3\\\hline 2 & 15 & 30 \\\hline 3 & 16 & 48\\ \hline 4 & 1 & 4 \\\hline 5 & 0 & 0 \\\hline 6 & 1 & 6 \\\hline & \sum Fx = 91&  \end{array}\)

\(\sum fx\) = 91

 

193.

A room is 12m long, 9m wide and 8m high. Find the cosine of the angle which a diagonal of the room makes with the floor of the room 

A.

\(\frac{15}{17}\)

B.

\(\frac{8}{17}\)

C.

\(\frac{8}{15}\)

D.

\(\frac{12}{17}\)

Correct answer is A

ABCD is the floor. By pathagoras 

AC\(^2\) = 144 + 81 = \(\sqrt{225}\) 

AC = 15cm

Height of room 8m, diagonal of floor is 15m

Therefore, the cosine of the angle which a diagonal of the room makes with the floor is 

EC\(^2\) = 15\(^2\) + 8\(^2\) cosine

\(\frac{adj}{Hyp} = \frac{15}{17}\) 

EC\(^2\) = \(\sqrt{225 + 64}\)

EC = \(\sqrt{289}\)

= 17 

194.

What is the circumference of latitude 0\(^o\)S if R is the radius of the earth? 

A.

cos \(\theta\)

B.

2\(\pi\)R cos \(\theta\)

C.

R sin \(\theta\)

D.

2 \(\pi\) r sin \(\theta\)

Correct answer is B

Circumstances of latitude 0\(^o\)s where R is the radius of the earth 2\(\pi\)r cos \(\theta\)

195.

Four boys and ten girls can cut a field first in 5 hours. If the boys work at \(\frac{5}{4}\) the rate at which the girls work, how many boys will be needed to cut the field in 3 hours? 

A.

180

B.

60

C.

25

D.

20

Correct answer is D

Let x rep. numbers of boys that can work at \(\frac{5}{4}\) the rate at

 which the 10 girls work 

For 1 hrs, x boys will work for \(\frac{\frac{1}{5} \times 10}{4}\) 

x = \(\frac{5}{4}\) x 10 

= 8 boys 

8 boys will do the work of ten girls at the same rate 

4 + 8 = 12 bous cut the field in 5 hrs for 3 hrs, 

\(\frac{12 \times 5}{3}\) boys will be needed = 20 boys.