2009 - JAMB Mathematics Past Questions and Answers - page 6
51
Simplify 7\(\frac{1}{12}\) - 4\(\frac{3}{2}\) + 2\(\frac{1}{2}\)
A
4
B
4\(\frac{1}{6}\)
C
4\(\frac{5}{6}\)
D
5\(\frac{1}{6}\)
correct option: c
7\(\frac{1}{12}\) - 4\(\frac{3}{2}\) + 2\(\frac{1}{2}\)
Take care of the whole numbers
7 - 4 + 2 = 5
therefore, 5\(\frac{1}{12}\) - \(\frac{3}{4}\) + \(\frac{1}{2}\)
LCM = 12
5\(\frac{1 - 9 + 6}{12}\)
4\(\frac{13 - 9 + 6}{12}\)
= 4\(\frac{10}{12}\)
or = 4\(\frac{5}{6}\)
Users' Answers & CommentsTake care of the whole numbers
7 - 4 + 2 = 5
therefore, 5\(\frac{1}{12}\) - \(\frac{3}{4}\) + \(\frac{1}{2}\)
LCM = 12
5\(\frac{1 - 9 + 6}{12}\)
4\(\frac{13 - 9 + 6}{12}\)
= 4\(\frac{10}{12}\)
or = 4\(\frac{5}{6}\)
52
Evaluate \(\frac{81.81 + 99.44}{20.09 + 36.16}\) correct to 3 significant figures.
A
6.21
B
3.22
C
2.78
D
2.13
correct option: b
\(\frac{81.81 + 99.44}{20.09 + 36.16}\)
= \(\frac{181.25}{56.25}\)
= 3.22
Users' Answers & Comments= \(\frac{181.25}{56.25}\)
= 3.22
53
A student spent \(\frac{1}{5}\) of his allowances on books, \(\frac{1}{3}\) of the remainder on food and kept the rest for contingences. What fraction was kept?
A
\(\frac{7}{16}\)
B
\(\frac{8}{15}\)
C
\(\frac{2}{3}\)
D
\(\frac{4}{5}\)
correct option: b
Spent \(\frac{1}{5}\) on books remaining \(\frac{4}{5}\)
spent \(\frac{1}{3}\) of \(\frac{4}{5}\) on food
\(\frac{4}{5}\) x \(\frac{1}{3}\) = \(\frac{4}{15}\)
therefore, \(\frac{4}{5}\) - \(\frac{4}{15}\)
= \(\frac{12 - 4}{15}\)
= \(\frac{8}{15}\)
Users' Answers & Commentsspent \(\frac{1}{3}\) of \(\frac{4}{5}\) on food
\(\frac{4}{5}\) x \(\frac{1}{3}\) = \(\frac{4}{15}\)
therefore, \(\frac{4}{5}\) - \(\frac{4}{15}\)
= \(\frac{12 - 4}{15}\)
= \(\frac{8}{15}\)
54
Solve 52(x - 1) x 5x + 1 = 0.04
A
\(\frac{1}{3}\)
B
\(\frac{1}{4}\)
C
-\(\frac{1}{5}\)
D
-\(\frac{1}{3}\)
correct option: d
52(x - 1) x 5x + 1 = 0.04
52x - 1 x 5x + 1 = \(\frac{1}{25}\)
53x - 1 = 5-2
3x - 1= -2
3x = -1
therefore, x = -\(\frac{1}{3}\)
Users' Answers & Comments52x - 1 x 5x + 1 = \(\frac{1}{25}\)
53x - 1 = 5-2
3x - 1= -2
3x = -1
therefore, x = -\(\frac{1}{3}\)
55
If log102 = 0.3010 and log107 = 0.8451, evaluate log10280.
A
3.4471
B
2.4471
C
1.4471
D
1.4071
correct option: b
log10(10 x 7 x 4)
log10280 = log1010 + log107 + 2 log 2
= 1 + 0.8451 + 2(0.3010)
= 2.4471
Users' Answers & Commentslog10280 = log1010 + log107 + 2 log 2
= 1 + 0.8451 + 2(0.3010)
= 2.4471
56
Simplify \(\frac{5 + \sqrt{7}}{3 + \sqrt{7}}\)
A
17 - \(\sqrt{7}\)
B
4 - \(\sqrt{7}\)
C
15 - \(\sqrt{7}\)
D
7 - \(\sqrt{7}\)
correct option: b
\(\frac{5 + \sqrt{7}}{3 + \sqrt{7}}\) x \(\frac{3 + \sqrt{7}}{3 + \sqrt{7}}\)
\(\frac{15 - 5 \sqrt{7} + 3\sqrt{7} - 7}{9 - 3\sqrt{7} + 3\sqrt{7} - 7
= 4 - 2\(\sqrt{7}\)
Users' Answers & Comments\(\frac{15 - 5 \sqrt{7} + 3\sqrt{7} - 7}{9 - 3\sqrt{7} + 3\sqrt{7} - 7
= 4 - 2\(\sqrt{7}\)
57
If x = {n2 + 1 : n is positive integer and 1\(\leq\) n \(\leq\) 5}
y = {5n : n is positive integer and 1 \(\leq\) n \(\leq\) 5}, find x ∩ y.
y = {5n : n is positive integer and 1 \(\leq\) n \(\leq\) 5}, find x ∩ y.
A
{5, 10}
B
{5, 10, 15}
C
{2, 5 ,10}
D
{5, 10, 15, 20}
correct option: a
X : (n2 + 1) = 2, 5, 10, 17, 26
y : 5n = 5, 10, 15, 20, 25
x ∩ y = (5, 10)
Users' Answers & Commentsy : 5n = 5, 10, 15, 20, 25
x ∩ y = (5, 10)
58
i. S∩T∩W = S
ii. S∪T∪W = W
ii. T∩W = S
If S\(\subset\)T\(\subset\)W. Which of the above statements are true?
ii. S∪T∪W = W
ii. T∩W = S
If S\(\subset\)T\(\subset\)W. Which of the above statements are true?
A
i and ii
B
i and iii
C
ii and iii
D
i, ii and iii
correct option: b
Users' Answers & Comments59
If P = \(\sqrt{\frac{rs^3}{t}}\), express r in terms of p, s and t.
A
\(\frac{p^2t}{s^3}\)
B
\(\frac{p^3t}{s^3}\)
C
\(\frac{p^3t}{s^2}\)
D
\(\frac{pt}{s^3}\)
correct option: a
P2 = \(\frac{rs^3}{t}\)
P2t = rs3
r = \(\frac{p^2t}{s^3}\)
Users' Answers & CommentsP2t = rs3
r = \(\frac{p^2t}{s^3}\)
60
A polynomial in x whose roots are \(\frac{4}{3}\) and -\(\frac{2}{5}\) is
A
15x2 - 11x - 12
B
15x2 + 11x - 12
C
12x2 - x - 12
D
12x2 + 11x - 15