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JAMB Mathematics Past Questions & Answers - Page 92

456.

If the 2nd term of a G.P is $\frac{8}{9}$ and the 6th term is 4 $\frac{1}{2}$ . Find the common ratio.

$\frac{3}{2}$

$\frac{2}{3}$

Correct answer is B

T₂ = $\frac{8}{9}$ , T₆ = 4 $\frac{1}{2}$
ar = $\frac{8}{9}$
ar⁵ = $\frac{9}{2}$

$\frac{ar}{ar^5}$ = $\frac{8}{9}$ x $\frac{2}{9}$

$\frac{1}{r^4}$ = $\frac{16}{81}$

r = $\sqrt[4]{18/16}$ = $\frac{3}{2}$

457.

In a school of 150 students, 80 offer French while 60 offer Arabic and 20 offer neither. How many students offer both subjects?

View answer & explanation

Correct answer is B

80 - x + x + 60 - x + 20 = 150 160 - x = 150 x = 160 - 150 = 10

458.

Find the derivative of y = ( $\frac{1}{3}$ X + 6) $^2$

2( $\frac{1}{3}$ X + 6

$\frac{2}{3}$ ( $\frac{1}{3}$ X + 6)

$\frac{2}{3}$ ( $\frac{1}{3}$ X + 6)²

$\frac{1}{3}$ ( $\frac{1}{3}$ X + 6)²

View answer & explanation

Correct answer is B

Y = ( $\frac{1}{3}$ X + 6) $^2$

$\frac{dy}{dx}$ = 2( $\frac{1}{3}$ X + 6) $\frac{1}{3}$

= $\frac{2}{3}$ ( $\frac{1}{3}$ X + 6)

459.

If the mean of 4, y, 8 and 10 is 7. Find Y?

View answer & explanation

Correct answer is A

$\frac{4 + y + 8 + 10}{4}$ = 7

22 + y = 4 x 7
22 + y = 28
y = 28 - 22 = 6

460.

Integrate $\frac{2x^3 + 2x}{x}$ with respect to x

$\frac{2x^3}{3}$ - 2x + k

x³ + 2x + k

$\frac{2x^3}{3}$ + 2x + k

x³ - 2x + k

View answer & explanation

Correct answer is C

$\int$ $\frac{2x^3 + 2x}{x}$ = $\int$ $\frac{2x^3}{x}$ + $\frac{2x}{x}$ = $\int$ (2x² + 2) dx

$\frac{2x^2+1}{2 + 1}$ + 2x + k

= $\frac{2x^3}{3}$ + 2x + k