JAMB Mathematics Past Questions & Answers - Page 232

1,156.

Two sisters, Taiwo and Keyinde, own a store. The ratio of Taiwo's share to Kehinde's is 11:9. Later, Keyinde sells \(\frac{2}{3}\) of her share to Taiwo for N720.00. Find the value of the store.

A.

N1,080.00

B.

N2,400.00

C.

N3,000.00

D.

N3,600.00

Correct answer is B

Let value of store = X

Ratio of Taiwo's share to kehine's is 11:9 Keyinde sells \(\frac{2}{3}\) of her share to Taiwo for N720

\(\frac{2}{3}\) of 9 = 6

∴ Sum of the ratio = 11 + 9 = 20

\{\frac{6}{20}\) of x = N720

\(\frac{6x}{20}\) = 720

∴ x = \(\frac{720 \times 20}{6}\)

x = N24,000

1,157.

A 5.0g of salt was weighted by Tunde as 5.1g. What is the percentage error?

A.

20

B.

2

C.

1.1

D.

0.2

Correct answer is B

% error = \(\frac{\text{actual error}}{\text{true value}}\) x 100

Where actual error = 5.1 - 5.0 = 0.1

true value = 5.0g

% error = \(\frac{0.1}{5.0}\) x 100

= \(\frac{10}{5}\)

= 2%

1,158.

Simplify \(\frac{1\frac{1}{2}}{2 \div \frac{1}{4} \text{of } 32}\)

A.

\(\frac{3}{256}\)

B.

\(\frac{3}{32}\)

C.

6

D.

85

Correct answer is C

\(\frac{1\frac{1}{2}}{2 \div \frac{1}{4} \text{ of }32}\)

= \(\frac{\frac{3}{2}}{2 \div \frac{1}{4} \times 32}\)

\(\frac{3}{2} \times 4 = 6\)

1,159.

For which of the following exterior angles is a regular polygon possible? i. 35° ii. 18° iii. 15°

A.

i and ii

B.

ii only

C.

ii and iii

D.

iii only

Correct answer is C

for a regular polygon to be possible, it must have all sides angles equal. \(\frac{360}{18}\) = 20 sides and \(\frac{360}{15}\) = 24 sides

(ii) and (iii) are right

1,160.

Four interior angles of a pentagon are 90o - xo, 90o + xo, 110o - 2xo, 110o + 2xo. Find the fifth interior angle

A.

110o

B.

120o

C.

130o

D.

140o

Correct answer is D

Let the fifth interior angle be y: sum of interior angle of a pentagon

= (2 x 5 - 4) x 90o

= 6 x 90o

= 540o

(90 - x) + (90 + x) + (110 - 2x) + (110 + 2x) + y = 540o

400o + y = 540o

y = 540 - 400o

y = 140o