JAMB Mathematics Past Questions & Answers - Page 261

1,301.

Make t the subject of formula S = ut + \(\frac{1}{2} at^2\)

A.

\(\frac{1}{a}\) (-u + \(\sqrt{U^2 - 2as}\))

B.

\(\frac{1}{a}\) {u \(\pm\) (U2 - 2as)}

C.

\(\frac{1}{a}\) {u \(\pm\) \(\sqrt{2as}\)}

D.

\(\frac{1}{a}\) {-u + \(\sqrt{( 2as)}\)}

Correct answer is A

Given S = ut + \(\frac{1}{2} at^2\)

S = ut + \(\frac{1}{2} at^2\)

∴ 2S = 2ut + at2

= at2 + 2ut - 2s = 0

t = \(\frac{-2u \pm 4u^2 + 2as}{2a}\)

= -2u \(\pi\) \(\frac{\sqrt{u^2 4u^2 + 2as}}{2a}\)


= \(\frac{1}{a}\) (-u + \(\sqrt{U^2 - 2as}\))

1,302.

Solve the equation: \(y - 11\sqrt{y} + 24 = 0\)

A.

8, 3

B.

64, 9

C.

6, 4

D.

9, -8

Correct answer is B

\(y - 11\sqrt{y} + 24 = 0 \implies y + 24 = 11\sqrt{y}\)

Squaring both sides,

\(y^{2} + 48y + 576 = 121y\)

\(y^{2} + 48y - 121y + 576 = 0 \implies y^{2} - 73y + 576 = 0\)

\(y^{2} - 64y - 9y + 576 = 0\)

\(y(y - 64) - 9(y - 64) = 0\)

\((y - 9)(y - 64) = 0\)

\(\therefore \text{y = 64 or y = 9}\)

1,303.

Factorize \(9p^2 - q^2 + 6qr - 9r^2\)

A.

(3p - 3q + r)(3p - q - 3r)

B.

(6p - 3q - 3r)(3p - q - 4r)

C.

(3p - q + 3r)(3p + q - 3r)

D.

(3q - p + 3r)(3q - p + 3r)

Correct answer is C

\(9p^{2} - q^{2} + 6qr - 9r^{2}\)

= \(9p^{2} - (q^{2} - 6qr + 9r^{2})\)

= \(9p^{2} - (q^{2} - 3qr - 3qr + 9r^{2})\)

= \(9p^{2} - (q(q - 3r) - 3r(q - 3r))\)

= \(9p^{2} - (q - 3r)^{2}\)

= \((3p + (q - 3r))(3p - (q - 3r))\)

= \((3p + q - 3r)(3p - q + 3r)\)

1,304.

If U = (1, 2, 3, 6, 7, 8, 9, 10) is the universal set. E = (10, 4, 6, 8, 10) and F = {x: 1x\(^{2}\) = 2\(^{6}, x is odd}. Find (E ∩ F)', where ' means the complement of a set.

A.

(0)

B.

U

C.

(8)

D.

\(\phi\)

Correct answer is D

U = (1, 2, 3, 6, 7, 8, 9, 10)

E = (10, 4, 6, 8, 10)

F = (x : x\(^2\) = 2\(^6\), x is odd)

∴ F = \(\phi\) Since x\(^2\) = 2\(^6\) = 64

x = \(\pm 8\) which is even

∴ E ∩ F = \(\phi\) Since there are no common elements

1,305.

If x = (all prime factors of 44) and y = (all prime factors of 60), the elements of X ∪ Y and X ∩ Y respectively are

A.

(2, 4, 3, 5, 11) and (4)

B.

(4, 3, 5, 11) and (3, 4)

C.

(2, 5, 11) and (2)

D.

(2, 3, 5, 11) and (2)

Correct answer is D

x = (all prime factors of 44) and y = (all prime factors of 60)

∴ x = (2, 11), y = (2, 3, 5)

X ∪ Y = (2, 3, 5, 11),

X ∩ Y = (2)