JAMB Mathematics Past Questions & Answers - Page 183

911.

A housewife bought 3 kilograms of garri at N13.00 per kg. She deposited N160. 00 for half a cow and bought 24 oranges at 10k each. She came back home with N20.60. She therefore left home with

A.

N220.00

B.

N222.00

C.

N201.40

D.

N202.00

E.

N180.80

Correct answer is B

3 kg of garri at N13.00 per kg = N39.00
half a cow = N160.00
24 oranges at 10k each = N2.40
balance = N20.60
Adding all together = N222.00

912.

The solution to the quadratic equation 5 + 3x - 2x2 = 0 is

A.

(\(\frac{5}{2}\), 1)

B.

(5, 3)

C.

-(\(\frac{5}{2}\), -1)

D.

(\(\frac{5}{2}\), -1)

Correct answer is D

5 + 3x - 2x2 = 0, (x + 1)(5 - 2x) (expand to check)

(x + 1)(5 - 2x) = 0

when x = 1 = 0, x = -1

when 5 - 2x = 0, x = \(\frac{5}{2}\) - 1

913.

Simplify \(\frac{3}{2x - 1}\) + \(\frac{2 - x}{x - 2}\)

A.

\(\frac{2 - x}{(2x - 1)(x - 2)}\)

B.

\(\frac{5 - x}{(2x - 1)(x - 2)}\)

C.

\(\frac{4 - 2x}{2x - 1}\)

D.

\(\frac{6 - 3x}{(2x - 1)(x - 2)}\)

Correct answer is C

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

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

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

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

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

= \(\frac{4 - 2x}{2x - 1}\)

914.

In a regular polygon of n sides, each interior angle is 144°. Find n

A.

12

B.

11

C.

10

D.

8

E.

6F

Correct answer is C

Formula for an interior angle of a polygon is (2n - 4) x 90

(2n - 4) x 90 = 144n

190n - 360 = 144n

n = \(\frac{360}{36}\)

= 10

915.

The diameter of a metal rod is measured as 23.40 cm to four significant figures. What is the maximum error in the measurement?

A.

0.05cm

B.

0.5cm

C.

0.045cm

D.

0.005cm

E.

0.004cm

Correct answer is D

Maximum error in measurement to 2 decimal places

Maximum error = \(\frac{1}{2}\) x 0.001

= 0.005