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NECO Mathematics Past Questions & Answers - Page 22

106.

Evaluate 1011two + 1101two + 1001two - 111two

A.

10001two

B.

11001two

C.

110001two

D.

11010two

E.

10001two

Correct answer is D

Convert each value to decimal (base 10)

1011two → 11

+ 1101two → 13

+ 1001two → 9

- 111two → 7

: 11 + 13 + 9 - 7 = 26

26 → 11010two

107.

Two similar cylindrical cans have heights of 7cm and 21cm, if the smaller holds 250g of sugar, how many kg of sugar will the larger one hold?

A.

0.75

B.

1.5

C.

2.25

D.

3.5

E.

6.75

Correct answer is E

- If two solids are similar, the ratio of their volumes is equal to the cube of the ratio of their corresponding sides.

Given: Heights of cylinder  -->     21 : 7 or  3 : 1 = 31 

                                = 3 times height enlargement

            Volume / Capacity of larger cylinder = 33 × 250g 

                                = 27 × 250g = 6,750 or 6.75kg

 

108.

If y varies inversely as x2, how does x vary with y?

A.

x varies inversely as y2

B.

x varies inversely as y

C.

x varies directly as y2

D.

x varies directly as y

E.

x varies directly as y

Correct answer is B

No explanation has been provided for this answer.

109.

The nth term of a sequence is given as 4×3(3n). Calculate the third term.

A.

12

B.

32

C.

4

D.

3

E.

1

Correct answer is C

4×3(3n)

for the third term, n = 3

then 

4×3(33)4×30 = 4 x 1 = 4.

 

110.

Two angles of a triangle are 45º each and its longest side is 12cm. Find the length of one of the other sides

A.

12cm

B.

92cm

C.

62cm

D.

6cm

E.

32cm

Correct answer is C

Two angles of a triangle are 45º each and its longest side is 12cm, this simply describes an isosceles triangle

two equal angles and two equal sides

using Pythagoras theorem,

x2+x2=122

 2x2 = 144

x2 = 72( after dividing b/sides by 2)

x = 72=62cm.