JAMB Mathematics Past Questions & Answers - Page 7

31.

The graph above depicts the performance ratings of two sports teams A and B in five different seasons

In the last five seasons, what was the difference in the average performance ratings between Team B and Team A?

A.

1.2

B.

6.4

C.

4.6

D.

1.8

Correct answer is A

Average performance rating of Team B = \(\frac{7+9+1+9+6}{5} = \frac{32}{5}\) = 6.4

Average performance rating of Team A = \(\frac{5+3+6+10+2}{5} = \frac{26}{5}\) = 5.2

∴ The difference in the average performance ratings between Team B and Team A = 6.4 - 5.2 = 1.2

32.

Express 16.54 x 10\(^{-5}\) - 6.76 x 10\(^{-8}\) + 0.23 x 10\(^{-6}\) in standard form

A.

1.66 x 10\(^{-4}\)

B.

1.66 x 10\(^{-5}\)

C.

1.65 x 10\(^{-5}\)

D.

1.65 x 10\(^{-4}\)

Correct answer is A

16.54 x 10\(^{-5}\) - 6.76 x 10\(^{-8}\) + 0.23 x 10\(^{-6}\)

⇒ 1.654 x 10\(^{-4}\) - 6.76 x 10\(^{-8}\) + 2.3 x 10\(^{-7}\)

⇒ 1.654 x 10\(^{-4}\) - 0.000676 x 10\(^{-4}\) + 0.0023 x 10\(^{-4}\)

⇒ (1.654 - 0.000676 + 0.0023) x 10\(^{-4}\)

∴ 1.655624 x 10\(^{-4}\) ≃ 1.66 x 10\(^{-4}\)

33.

The third term of an A.P is 6 and the fifth term is 12. Find the sum of its first twelve terms

A.

201

B.

144

C.

198

D.

72

Correct answer is C

T\(_3\) = 6

T\(_5\) = 12

S\(_{12}\) = ?

T\(_n\) = a + (n - 1)d

⇒ T\(_3\) = a + 2d = 6 ----- (i)

⇒ T\(_5\) = a + 4d = 12 ----- (ii)

Subtract equation (ii) from (i)

⇒ -2d = -6

⇒ d\(\frac{-6}{-2}\) = 3

Substitute 3 for d in equation (i)

⇒ a + 2(3) = 6

⇒ a + 6 = 6

⇒ a = 6 - 6 = 0

S\(_n\) = \(\frac{n(2a + (n - 1)d)}{2}\)

⇒ S\(_{12}\) = \(\frac{12(2 \times 0 + (12 - 1)3)}{2}\)

⇒ S\(_{12}\) = 6(0 + 11 x 3)

⇒ S\(_{12}\) = 6(33)

∴ S\(_{12}\) = 198

34.

Find the volume of the cylinder above
[Take \(\pi= ^{22}/_7\)]

A.

9,856 cm\(^3\)

B.

14,784 cm\(^3\)

C.

4,928 cm\(^3\)

D.

19,712 cm\(^3\)

Correct answer is B

Volume of the cylinder = \(\frac{θ}{360} \times \pi r^2h\)

θ = 360\(^o\) - 90\(^o\) = 270\(^o\)

∴ Volume of the cylinder = \(\frac{270}{360} \times \frac{22}{7} \times \frac{14^2}{1} \times \frac{32}{1} = \frac{37,255,680}{2520} = 14,784cm^3\)

35.

Find the compound interest (CI) on ₦15,700 for 2 years at 8% per annum compounded annually.

A.

₦6,212.48

B.

₦2,834.48

C.

₦18,312.48

D.

₦2,612.48

Correct answer is D

Principal (P) = ₦15,700

Rate (R) = 8

Number of years (t) = 2

A = P \((1+\frac{R}{100})^t\)

⇒ A = 15700 \((1+\frac{8}{100})^2\)

⇒ A = 15700 (1 + 0.08)\(^2\)

⇒ A = 15700 (1.08)\(^2\)

⇒ A = 15700 x 1.1664

⇒ A = ₦18,312.48

Total amount, A = ₦18,312.48

A = P + CI

⇒ CI = A - P

⇒ CI = 18,312.48 - 15,700

∴ CI = ₦2,612.48