WAEC Further Mathematics Past Questions & Answers - Page 66

326.

A force F acts on a body of mass 12kg increases its speed from 5 m/s to 35 m/s in 5 seconds. Find the value of F.

A.

36 N

B.

48 N

C.

72 N

D.

108 N

Correct answer is C

\(F = ma \)

\(a = \frac{v - u}{t}\)

\(\therefore F = m(\frac{v - u}{t})\)

\(F = 12(\frac{35 - 5}{5}) = 12 \times 6 = 72 N\)

327.

Two balls are drawn, from a bag containing 3 red, 4 white and 5 black identical balls. Find the probability that they are all of the same colour.

A.

\(\frac{5}{33}\)

B.

\(\frac{13}{66}\)

C.

\(\frac{8}{53}\)

D.

\(\frac{19}{66}\)

Correct answer is D

\(P(\text{two same color balls}) = P(\text{2 red}) + P(\text{2 white}) + P(\text{2 black})\)

\(P(\text{2 red}) = \frac{3}{12} \times \frac{2}{11} = \frac{1}{22}\)

\(P(\text{2 white}) = \frac{4}{12} \times \frac{3}{11} = \frac{1}{11}\)

\(P(\text{2 black}) = \frac{5}{12} \times \frac{4}{11} = \frac{5}{33}\)

\(P(\text{2 same color balls}) = \frac{1}{22} + \frac{1}{11} + \frac{5}{33} = \frac{19}{66}\)

328.

Eight football clubs are to play in a league on home and away basis. How many matches are possible?

A.

14

B.

28

C.

56

D.

128

Correct answer is C

Number of matches possible = \(2 \times ^{8}C_{2}\) (Home and away repitition of the matches)

= \(2 \times \frac{8!}{(8 - 2)! 2!}\)

= \(2 \times 28\)

= 56

329.

If the mean of -1, 0, 9, 3, k, 5 is 2, where k is a constant, find the median of the set of numbers.

A.

\(\frac{3}{2}\)

B.

0

C.

\(\frac{7}{2}\)

D.

6

Correct answer is A

\(\frac{-1 + 0 + 9 + 3 + k + 5}{6} = 2 \implies 16 + k = 12\)

\(k = -4\)

Arranging -1, 0, 9, 3, -4, 5 in order: -4, -1, 0, 3, 5, 9

Median = \(\frac{0 + 3}{2} = \frac{3}{2}\)

330.

Evaluate \(\begin{pmatrix} 2 & 3 \\ 4 & 1 \end{pmatrix} \begin{pmatrix} 2 \\ 3 \end{pmatrix}\). 

A.

(13, 11)

B.

(11, 13)

C.

\(\begin{pmatrix} 13 \\ 11 \end{pmatrix}\)

D.

\(\begin{pmatrix} 11 \\ 13 \end{pmatrix}\)

Correct answer is C

\(\begin{pmatrix} 2 & 3 \\ 4 & 1 \end{pmatrix} \begin{pmatrix} 2 \\ 3 \end{pmatrix}\)

= \(\begin{pmatrix} 2 \times 2 + 3 \times 3 \\ 4 \times 2 + 1 \times 3 \end{pmatrix}\)

= \(\begin{pmatrix} 13 \\ 11 \end{pmatrix}\)