真二第張七第一日二月正年午戊复

WAH KIU YAT PO

報日僑華

育教僑華

yim x + 150 is the required additional linear graph

From the groph, 66 students

(55

二期星

11

2. If

find the values

of students) have marke below 36.

ab ̈a+

日八廿月二年八七九一展公年七十六國民華中 華

14.

the shadow of the shorter

Find

pole is 4im Long.

the bearing of the shadow

cast by the rope.

A

MHI & Dale Prest

1978

P U S Š.81 27

新數學 廿二 魯榮家

MODERN HATHEMATICS (22) Answers to Exercise 8 (cont.) 10.(1) Let the height of the conical vessel' be h. cm, vol-

ume of water contained be V. Since, for similar solids, (volume ratio)

= (corresponding side ratio)3.

120 : V h3: (*h)?

·V 15 cm (Ang.)

(11) Let the sum of volume of

water contained and the total

volume of the spheres be V!

Since depth of water

From the graph, there is no. intersection between the

curve and the linear graph. Therefore, there is no such value of x which gives the area of the rhombus 6cm2.

Note: Since the area of the

rhombus is:

Area =3x(5

the pass mark required = 36. (Ans.)

(b) The pass percentage is

45%%

(o) From the graph,114students (95% of the students) with marks less then 54, there

fore the range for grade "A 18

marks greater or equal to 54.

15. (a) E

The maximum value of the.

expression

AD =2

2BC

2(c-b)

26 + 20

20+ 20

26 +

(Ans.)

(b) AC-AB

19 3.125.

Therefore, the maximum area of a rhombus with sum of

lengths of diagonals equal to 5om 1s 3.125 cm

(AC) (AB)008 LBAC

thx 1.1

11

120 VI

b3 (1) 3

1331

x 120

it is impossible that the area is 6 cm2

and therefore.

(AB) (AC COB L BAC)

no solution is obtained from the graph.

=

(AB)2

of +5

3. Three pieces of string, the length of which are

4

gem, 6cm and 33cm respectively, are cut into pieces which are all of the same length. Find in cm the greatest length that these pieces can have, und how many of them the re

are,

4. A hemispherical bowl,

diameter 6cm full of water, is emptied into an empty cylindricel glass of radius 4cm both measurements being internal. Find the depth of water in the glass.

5. Simplify

(1-tanx) +(1

(1-cotx) +(1+cotx)"

10cm B

8cm

15.

In the figure, ZABC-61",

ZACR=35. ·Find the ratio Bir -26-

.CD

In the figure, ABPC is cyclic quadrilateral. PXLAB; PYLBC, PZLAC, Prove that ⠀;

(a) 4PX 4PCA

(b)X, Y, Z are collinear.

16.

8000

19.965 cm

Let the radius of each sphe

be r att

Total volume of the spheres

=19.965 15 = 4.965

3(Tr3) = 4.965

= 0.3951

0.7338 cm (Ans.)

11. (a) Slope of PA

00m

= 100 (ins.)

(0)

Since BFFE ED = DC

DF 1 F3 21

AT

2AB+ AD

3

2AB+ AD = 3AF

(1) In rt. A ABC-

Slope of PB =

BC AC

2013 + 5AD

COS LACB.

PA is perpendicular

BC 100 x coв 53

5(2AB 25AP

AD) (Ans.)

= 60 cm

16.

(b)Since

to FB

( - )2 + 1) - -1

+y -

25.

Hence, it is a circle with

centre at (0,0) and radius

255

(0)

From (1)

4x + 3y

2

13.

2

= 25

J4 or -4

Substitute into` (1)

3 or 3

C, D are the points (-3,4), (3,-4)

(a) The mid-point of OD is

(2244)

(0,0).

the centre of the circle

1. CD is one of the diameters

12.(a) Let the lengths of the diagonala of the rhombus be respectively.

x cm and y C

x + y = 5

or y 5 x

Area of the Tombus

≈ 4x ()()(dy)

G

dxy = x(5 - x)

.. Area 與

ст "(Año)

*x(5 - x) on2

(b) If area of the rhombus is

*

6 cm

cm2 then

6

ax(5 - x).

6 m

52 + 12 = 0

Since the given graph is

y = x 4x - 3

-

2

y = x + 15

- X

*

In rt. A BCF

FC

=tan 30°

FC = 60 x ten 30°

60 x 0.5773 = 34.64cm.

In rt. A FAC

tan

FC FACC

4 FAC.=

=

34.64 100

= 0.3464

1967

(ii) Aren or ABCF

30 x CF

≈ x 60 x 34,64

2 =1039.2 cm

Volume of the solid

(Ans.)

CD x Area of ▲ BCF

AB

sin ACB = 0.8

AB AC x 0.8 = 80cm = CD

Volume 80 x 1039.2

03136 cm3 (Ans.)

14.(1) From the given graph

Larks

988988

Number of students with marks below

C

30

140

50

As shown in the Venn diagram, M set of students taking

mathematics.

7- set of students taking

physics.

n(K) 70, n(P) 50.

n(MAP) = 30, n(Ṁ v P)=90 (1) Number of students taking neither mathematics nor physics = 50 (Ane.)

(11) Number of students tak- ing eithèr mathematics or

physios but not both.

= 90 - 30, 60 (Ans.) (iii) The probability that a student picked at random and that he is teking physics but not mathematics

20

H

140

(Ans.)

(iv) Among the students not

taking physics, the probability

that a student takes matha.

40

140-50

this mart

10

14

20

30

30

48

40

78

(Ane.)

50

110

60

120

數學

二十二女長波

(11)(a)

Mathematics 22

Exercise 10

Attempt all questions in Section A and any six questions in Section B. Section A

1. If the equation

(m−1)x2+2(m+1)x-1=0` have two unequal real roots, find the values of mi

In the figure, ABCB is. square, Calculate LDPC.

Ө

The radii of the circular

arcs in the given figure

are equal and their centres

lie on AR If AB-10cm

CD-4cm, calculate the

radius of each arc.

(Geometry Theorem need not

be quoted when used,

the figure, AT and BP are the tangents of the circle at A and B.. If

LATO=35, 4TOR-115, find ZBPO (Geometry Theorem need not be quoted when used.)

Section B

9. The total cost of making

a certain article consista partly of a constant sum independent of the size of the article and partly of a sum which varies as the cube of the length of the article. If the cost is $25 when the length is len and 851 when the length is 3cm,

what will it be when the length iá 8cm?

a 3b * 3b+2c £c+a 8+56 show that x must equal either or −1,

10. If x

11. Two towns X and Y are 40 km apart. A car leaves X at 9a.m. travelling towards. Y at an average "speed of 30km/hr. 30min.

later a car leaves Y travelling towards X art an average speed of 45km 45km/lir.. When the cars meet the drivers talk for 10min., then each returns to his starting- point, both arriving back at 10:20a.. Find graphically.

(a)The time at which the

cars meet.. (b)The distance from X

when the cara meet. (c)The average speed at

which each car travels on the return journey. 12.An estate was bought by a man for $240,000. He sold of the estate at a gain of 20% and of it

5

at a loss of 15%. At what gain percent must be sell the remainder so as to make a profit of 10% on the whole.

13.Two vertical poles 6n, 10m high stand on level ground 5m apart on the East-West linei a tight rope connec connects their tops;

when the sun is due South

In the figure, BC is the

diameter of the circle..

AD//BC and CE the tangent

of the circle at C.

Prove that: BC-AE-BD2.

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下列每題有五個項目,其中一個和其余四 個並不同類;試選出選個不同類的項目。

B奔吧 【例一】A愉快

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(B) 黯解:愉快、愁閂、輕鬆、高興都是與情緒

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【例二】A眼睛 B榮:

D 指甲

E眉毛

(D) 题解:眼睛、耳朵、鼻子、走都是人的五

官之一,而指甲不是。答案應避D。

C鼻子

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