JAMB Mathematics Past Questions & Answers - Page 383

1,911.

If m = 3, p = -3, q = 7 and r = 5/2, evaluate m(p+q+r)

A.

19.50

B.

19.15

C.

18.95

D.

18.05

Correct answer is A

m = 3, p = -3, q = 7 and r = 5/2
m(p+q+r) = 3(-3 + 7 + 5/2)
= 3(4 + 5/2)
= 3(4 + 21/2)
= 3 * 61/2
= 3 * 13/2
= 39/2
= 19.50

1,912.

Simplify \(\frac{(√12-√3)}{(√12+√3)}\)

A.

zero

B.

1/3

C.

3/5

D.

1

Correct answer is B

\(\frac{(\sqrt{12}-\sqrt{3})}{(\sqrt{12}+\sqrt{3})}=\frac{\sqrt{4\times 3}-\sqrt{3}}{\sqrt{4\times 3}+\sqrt{3}}\\=\frac{2\sqrt{3}-\sqrt{3}}{2\sqrt{3}+\sqrt{3}}\\=\frac{\sqrt{3}}{3\sqrt{3}}\\=\frac{1}{3}\)

1,913.

If Log102 = 0.3010 and Log103 = 0.4771, evaluate Log104.5

A.

0.9542

B.

0.6532

C.

0.4771

D.

0.3010

Correct answer is B

Log102 = 0.3010 and Log103 = 0.4771
Log104.5 = Log1041/2
= Log109/2
= Log109 - Log102
= log1032 - Log102
= 2Log103 - Log102
= 2(0.4771) - 0.3010
= 0.9542 - 0.3010
= 0.6532

1,914.

Evaluate \(\frac{(81^{\frac{3}{4}}-27^{\frac{1}{3}})}{3 \times 2^3}\)

A.

3

B.

1

C.

1/3

D.

1/8

Correct answer is B

\(\frac{81^{\frac{3}{4}}-27^{\frac{1}{3}}}{3 \times 2^3} = \frac{(3^{3-\frac{3}{4}}-3^{3-\frac{3}{4}})}{3\times 2^3}\\=\frac{3^3 - 3}{3 \times 8}\\=\frac{27-3}{24}\\=\frac{24}{24}\\=1\)

1,915.

Three boys shared some oranges. The first received 1/3 of the oranges and the second received 2/3 of the remaining. If the third boy received the remaining 12 oranges, how many oranges did they share

A.

60

B.

54

C.

48

D.

42

Correct answer is B

Let x = the number of oranges
The 1st received 1/3 of x = 1/3x
∴Remainder = x - 1/3x = 2x/3
The 2nd received 2/3 of 2x/3 = 2/3 * 2x/3 = 4x/3
The 3rd received 12 oranges
∴1/3x + 4x/9 + 12 = x
(3x + 4x + 108)/9 = x
3x + 4x + 108 = 9x
7x + 108 = 9x
9x - 7x = 108
2x = 108
x = 54 oranges