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JAMB Mathematics Past Questions & Answers - Page 100

496.

Given that A = {3, 4, 1, 10, ⅓ }

B = {4, 3,⅓, ⅓, 7}.

Find A∩B

{}

{⅓, 1, 2}

{3, 4, ⅓}

{1, 3, ⅓}

View answer & explanation

Correct answer is C

A ∩ B = {3, 4, ⅓}

497.

One bag contain 3 blue and 5 red balls, another bag contain 2 blue and 4 red balls respectively. One ball is drawn for each bag. What is the probability both balls are blue

$\frac{2}{15}$

$\frac{3}{24}$

$\frac{3}{21}$

$\frac{3}{28}$

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.

498.

Simplify $[1 ÷ (x^2 + 3x + 2)] + [1 ÷ (x^2 + 5x + 6)]$

$\frac{2}{(x + 1)^2}$

$\frac{2}{(x + 1)(x + 2}$

$\frac{2}{(x + 1)(x + 3}$

View answer & explanation

Correct answer is D

$[1 ÷ (x^2 + 3x + 2)] + [1 ÷ (x^2 + 5x + 6)]$

= $1 ÷ (x^2 + 3x + 2) + [1 ÷ (x^2 +5x + 6)]$

= $[1 ÷ ((x^2 + x) + (2x + 2) )] + [1 ÷ ((x^2 + 3x) + (2x + 6) )]$

= [1 ÷ (x(x + 2) + 2(x +1))] + [1 ÷ (x(x + 3) +2(x + 3) )]

= [1 ÷ (x + 1)(x + 2)] + [1 ÷ ((x + 3) + (x + 2))]

=((x + 3) + (x + 1)) ÷ (x + 1)(x + 2)(x + 3)

Using the L.C.M

=((x + x + 3 + 1)) ÷ (x + 1)(x + 2)(x + 3)

=(2x+4)/(x+1)(x+2)(x+3) =2(x+2)/(x+1)(x+2)(x+3)

= $\frac{2 }{(x + 1)(x + 3)}$