JAMB Mathematics Past Questions & Answers - Page 50

246.

Find the value of \(\frac{(0.5436)^3}{0.017 \times 0.219}\) to 3 significant figures.

A.

46.2

B.

43.1

C.

534

D.

431

Correct answer is B

(\frac{(0.5436)^3}{0.017 \times 0.219}\)

= \(\frac{0.16063}{0.017 \times 0.219}\)

= 43.1 (to 3 s.f)

247.

Simplify 81\(^{\frac{-3}{4}}\) x 25\(^{\frac{1}{2}}\) x 243\(^{\frac{2}{5}}\)

A.

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

B.

\(\frac{3}{5}\)

C.

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

D.

\(\frac{5}{3}\)

Correct answer is D

81\(^{\frac{-3}{4}}\) x 25\(^{\frac{1}{2}}\) x 243\(^{\frac{2}{5}}\)

= \((\sqrt[4]{81})^{-3} \times \sqrt{25} \times (\sqrt[5]{243})^2\)

= \(\frac{5 \times 3^2}{3^{3}}\)

= \(\frac{5}{3}\)

248.

The simple interest on ₦8550 for 3 years at x% per annum is ₦4890. Calculate the value of x to the nearest whole number.

A.

19%

B.

20%

C.

25%

D.

16.3%

Correct answer is A

S.I = \(\frac{PRT}{100}\)

\(\implies\) N 4890 = \(\frac{8550 \times 3 \times x}{100}\)

\(x = \frac{4890 \times 100}{8550 \times 3}\)

\(x = 19.06%\)

\(x \approxeq 19%\)

249.

Tade bought 200 mangoes at 4 for ₦2.50. 30 out of the mangoes got spoilt and the remaining were sold at 2 for ₦2.40. Find the percentage profit or loss.

A.

43.6% loss

B.

35% profit

C.

63.2% profit

D.

28% loss

Correct answer is C

200 mangoes at 4 for N2.50

\(\implies\) Total cost price = \(\frac{200}{4} \times N 2.50\)

= N 125.00

Since 30 mangoes got spoilt \(\implies\) Left over = 200 - 30

= 170 mangoes 

170 mangoes at 2 for N 2.40

\(\implies\) Total selling point = \(\frac{170}{2} \times N 2.40\)

= N 204.00

Profit : N (204.00 - 125.00) = N 79.00

% profit = \(\frac{79}{125} \times 100%\)

= 63.2% profit.

250.

If P varies inversely as the square root of q, where p = 3 and q = 16, find the value of q when p = 4.

A.

12

B.

8

C.

9

D.

16

Correct answer is C

\(p \propto \frac{1}{\sqrt{q}}\)

\(\implies p = \frac{k}{\sqrt{q}}\)

when p = 3, q = 16.

\(3 = \frac{k}{\sqrt{16}}\)

\(k = 3 \times 4 = 12\)

\(\therefore p = \frac{12}{\sqrt{q}}\)

when p = 4,

\(4 = \frac{12}{\sqrt{q}} \implies \sqrt{q} = \frac{12}{4}\)

\(\sqrt{q} = 3 \implies q = 3^2 \)

\(q = 9\)