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JAMB Mathematics Past Questions & Answers - Page 174

866.

Marks scored by some children in an arithmetic test are:5, 3, 6, 9, 4, 7, 8, 6, 2, 7, 8, 4, 5, 2, 1, 0, 6, 9, 0, 8.
The arithmetic mean of the marks is

A.

6

B.

5

C.

8

D.

7

E.

10

Correct answer is B

Add all the No.s together to give 100

xf = 100

N = 20

x = xfN

= 10020

= 5

867.

What is the area between two concentric circles of diameters 26cm and 20cm?

A.

100π

B.

169π

C.

69π

D.

9π

E.

269π

Correct answer is C

Area of circle 1 with diameter 26cm:

πr2=π×(262)2

= 169πcm2

Area of circle 2 with diameter 20 cm:

πR2=π×(202)2

= 100πcm2

Area between the two circles = (169100)πcm2

= 69πcm2

868.

Evaluate correct to 4 decimal places 827.51 x 0.015

A.

8.8415

B.

12.4127

C.

124.1265

D.

12.4120

E.

114.1265

Correct answer is B

827.51 x 0.015 By normal multiplication or use of four figure table, 827.51 x 0.015 = 12.4127 (to 4 decimal places).

869.

A cuboid has a diagonal of length 9cm and a square base of side 4cm. What is its height?

A.

9cm

B.

65cm

C.

42cm

D.

7cm

E.

6.5cm

Correct answer is B

Given a cuboid, the diagonal cuts a face of the cuboid into 2 right-angled triangles.

Hence, using the Pythagoras theorem, we have

92=42+x2

81=16+x2

x2=8116=65

870.

Which of the following fractions is less than one-third?

A.

\frac{22}{63}

B.

\frac{4}{11}

C.

\frac{15}{46}

D.

\frac{33}{98}

E.

\frac{122}{303}

Correct answer is C

All others are greater than 0.333 when converted to their fractions except \frac{15}{46}