2011 - JAMB Mathematics Past Questions and Answers - page 1

1
If 2q35 = 778, find q
A
2
B
1
C
4
D
O
correct option: a

2q35 = 778

2 x 52 + q x 51 + 3 x 50 = 7 x 81 + 7 x 80

2 x 25 + q x 5 + 3 x 1 = 7 x 8 + 7 x 1

50 + 5q + 3 = 56 + 7

5q = 63 - 53

q = (\frac{10}{5})

q = 2

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2
Simplify \(\frac{3\frac{2}{3} \times \frac{5}{6} \times \frac{2}{3}}{\frac{11}{15} \times \frac{3}{4} \times \frac{2}{27}}\)
A
\(5\frac{2}{3}\)
B
30
C
\(4\frac{1}{3}\)
D
50
correct option: d

(\frac{3\frac{2}{3} \times \frac{5}{6} \times \frac{2}{3}}{\frac{11}{15} \times \frac{3}{4} \times \frac{2}{27}})

(\frac{\frac{11}{3} \times \frac{5}{6} \times \frac{2}{3}}{\frac{11}{15} \times \frac{3}{4} \times \frac{2}{27}})

(\frac{110}{54} \div \frac{66}{1620})

50

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3
A man invested N5,000 for 9 months at 4%. What is the simple interest?
A
N150
B
N220
C
N130
D
N250
correct option: a

S.I. = (\frac{P \times R \times T}{100})

If T = 9 months, it is equivalent to (\frac{9}{12}) years

S.I. = (\frac{5000 \times 4 \times 9}{100 \times 12})

S.I. = N150

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4
If the numbers M, N, Q are in the ratio 5:4:3, find the value of \(\frac{2N - Q}{M}\)
A
2
B
3
C
1
D
4
correct option: c

M:N:Q == 5:4:3

i.e M = 5, N = 4, Q = 3

Substituting values into equation, we have...

(\frac{2N - Q}{M})

= (\frac{2(4) - 3}{5})

= (\frac{8 - 3}{5})

= (\frac{5}{5})

= 1

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5
Simplify \((\frac{16}{81})^{\frac{1}{4}} \div (\frac{9}{16})^{-\frac{1}{2}}\)
A
\(\frac{2}{3}\)
B
\(\frac{1}{2}\)
C
\(\frac{8}{9}\)
D
\(\frac{1}{3}\)
correct option: b

((\frac{16}{81})^{\frac{1}{4}} \div (\frac{9}{16})^{-\frac{1}{2}})

((\frac{16}{81})^{\frac{1}{4}} \div (\frac{16}{9})^{\frac{1}{2}})

((\frac{2^4}{3^4})^{\frac{1}{4}} \div (\frac{4^2}{3^2})^{\frac{1}{2}})

(\frac{2^{4 \times \frac{1}{4}}}{3^{4 \times \frac{1}{4}}} \div \frac{4^{2 \times \frac{1}{2}}}{3^{2 \times \frac{1}{2}}})

(\frac{2}{3} \div \frac{4}{3})

(\frac{2}{3} \times \frac{3}{4})

(\frac{2}{4})

(\frac{1}{2})

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6
If log318 + log33 - log3x = 3, Find x.
A
1
B
2
C
o
D
3
correct option: b

log({3}^{18}) + log({3}^{3}) - log(_{3}^{x}) = 3

log({3}^{18}) + log({3}^{3}) - log(_{3}^{x}) = 3log33

log({3}^{18}) + log({3}^{3}) - log(_{3}^{x}) = log333

log3((\frac{18 \times 3}{X})) = log333

(\frac{18 \times 3}{X}) = 33

18 x 3 = 27 x X

x = (\frac{18 \times 3}{27})

= 2

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7
Rationalize \(\frac{2 - \sqrt5}{3 - \sqrt5}\)
A
\(\frac{1 - \sqrt5}{2}\)
B
\(\frac{1 - \sqrt5}{4}\)
C
\(\frac{ \sqrt5 - 1}{2}\)
D
\(\frac{1 + \sqrt5}{4}\)
correct option: b

(\frac{2 - \sqrt5}{3 - \sqrt5}) x (\frac{3 + \sqrt5}{3 + \sqrt5})

(\frac{(2 - \sqrt5)(3 + \sqrt5)}{(3 - \sqrt5)(3 + \sqrt5)}) = (\frac{6 +2\sqrt5 - 3\sqrt5 - \sqrt25}{9 + 3\sqrt5 - 3\sqrt5 - \sqrt25})

= (\frac{6 - \sqrt5 - 5}{9 - 5})

= (\frac{1 - \sqrt5}{4})

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8
Simplify (\(\sqrt2 + \frac{1}{\sqrt3})(\sqrt2 - \frac{1}{\sqrt3}\))
A
\(\frac{7}{3}\)
B
\(\frac{5}{3}\)
C
\(\frac{5}{2}\)
D
\(\frac{3}{2}\)
correct option: b

((\sqrt2 + \frac{1}{\sqrt3})(\sqrt2 - \frac{1}{\sqrt3}))

(\sqrt4 - \frac {\sqrt2}{\sqrt3} + \frac {\sqrt2}{\sqrt3} - \frac {1}{\sqrt9})

= 2 - (\frac {1}{3})

= (\frac {16 - 1}{3})

= (\frac{5}{3})

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9
Raial has 7 different posters to be hanged in her bedroom, living room and kitchen. Assuming she has plans to place at least a poster in each of the 3 rooms, how many choices does she have?
A
49
B
170
C
21
D
210
correct option: d

The first poster has 7 ways to be arranges, the second poster can be arranged in 6 ways and the third poster in 5 ways.

= 7 x 6 x 5

= 210 ways

or (\frac{7}{P_3}) = (\frac{7!}{(7 - 3)!}) = (\frac{7!}{4!})

= (\frac{7 \times 6 \times 5 \times 4!}{4!})

= 210 ways

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10
Make R the subject of the formula if T = \(\frac {KR^2 + M}{3}\)
A
\(\sqrt\frac{3T - K}{M}\)
B
\(\sqrt\frac{3T - M}{K}\)
C
\(\sqrt\frac{3T + K}{M}\)
D
\(\sqrt\frac{3T - K}{M}\)
correct option: b

T = (\frac{KR^2 + M}{3})

3T = KR2 + M

KR2 = 3T - M

R2 = (\frac{3T - M}{K})

R = (\sqrt\frac{3T - M}{K})

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