Tag Archives: word problems

Primary 5 CA1 Revision 12

P5-CA1-Ex12

Ans:

1–  $384

Christina –>  1u

Molly ->  3 u

Jack –>  1u + $65

5u + $65 = $705

5u –>  $705 – $65 = $640

1u –>  $640/5 = $128

$128 × 3 = $384

 

2–  235 paper clips

Before:                      Tom               :                   Jenny
1                   :                           5

——->     2                  :                         10

After:                             1                   :                           2

——>      5                  :                       10

5u – 2u = 4u

3u –>  141 clips

1u –>  47 clips

47 × 5 = 235 paper clips

 

3–  $60

3u –>  $36

1u –>  $12

$12 × 5 = $60

 

4–  9 years’ time

[Constant Difference]

3u –>  51 years

1u –>  17 years old

17 – 8 = 9 years’ time

 

5–  See belowQn 5

 

 

 

 

 

 

 

 

 

6–  18 coins

Multiples of 5 –>  5         10           15
+ 3  ->  8         13           18

Multiples of 4 –>   4         8             12            16
+ 2 ->   6         10          14           18

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Primary 6 August Problem Sums 9

P6-PSP-Aug-Ex 9

Ans:

1– 28 cm

Square numbers are 1, 4, 9, 16, 25, 36, 49, 64, 81, etc …

The two possible square numbers that add to 74 are 25 and 49

5 cm × 5 cm = 25 cm²

7 cm × 7 cm = 49 cm²

7 cm × 4 = 28 cm

 

2–  355 more marbles

Number of boys –>  3 + 5 = 8

Units of marbles each girl received –>  1u

Units of marbles each boy received –>  1u + 30

Total received by the 8 children –>  1u × 3 + (1u + 30) × 5 = 8u + 150

8u + 150 marbles ->  570 marbles

8u –>  570 – 150 = 420 marbles

1u –>  102.5 marbles

(5u + 150) – 3u = 2u + 150

(102.5 × 2) + 150 = 355 more marbles

 

3–  $71.50

7 durians + 10 mangoes –>  $57

[1 durian + 1 mango –>  $7.50] × 7
–>  7 durians + 7 mangoes –>  $52.50

Therefore, $57 – $52.50 = $4.50 –>  3 mangoes

1 mango–>  $4.50/ 3 = $1.50

1 durian –>  $7.50 – $1.50 = $6

4 durians + 3 mangoes –>  $6 × 4+ $1.50 × 3 = $28.50

$100 – $28.50 = $71.50

 

4–  15 : 6 : 10

Red   :  Blue                      Blue   :   Purple
5      :     2                             3      :      5

–>  15    :     6                             6      :    10

Red   :   Blue   :   Purple
15   :    6    :   10

 

5–  56 cm

Height of water level at first –>  5/8 × 64 cm = 40 cm

1600 cm³ ÷ (10 × 10) cm² = 16 cm

16 cm + 40 cm = 56 cm

 

6–  200 cookies

[Constant Difference]

At first:

Joanna –>  250 cookies

Sharon ->  350 cookies

In the end –>        Joanna  :  Sharon
3       :         5

2u –>  100

1u –>  50

8u –>  50 × 8 = 400 cookies left

600 – 400 = 200 cookies

 

7–  $13.50

5 small towels + 6 big towels –>  $34.50

6 small towels + 5 bog towels –>  $34.50 – $4 = $31.50

11 small towels + 11 big towels –>  $34.50 + $31.50 = $66

1 small towel + 1 big towel –> $66/ 11 = $6

5 small towels + 5 big towels –>  $6 × 5 = $30

1 big towel –> $34.50 – $30 = $4.50

$4.50 × 3 = $13.50

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Primary 4 CA2 Revision 3

P4-CA2-Ex 3

Ans:

1–  376 women
Qn 1

 
11u –>  2068

1u –>  188

188 × 2 = 376 women

 

2–  $49

Cost of 25 crates of apples –>  $58 × 25 = $1450

Cost of 3 crates of oranges —  $1597 – $1450 = $147

$147 ÷ 3 = $49

 

3–  $17

Cost of 6.5 kg of prawns –>  $24 × 6.5 kg = $156

Cost of 2 kg of fish –>  $190 – $156 = $34

$34 ÷ 2 = $17 

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Primary 6 Prelims Revision 9

P6-Prelims-Ex 9

Ans:

1– $45

Julian –>  1u

Frederick –>  2u

Marcus –>  6u

5u –> $25

1u –>  $5

$5 × 9u = $45

 

2–  16 more tricycles

Assume all are tricycles –> 56 × 3 = 168 wheels

168 – 148 = 20 wheels extra

Each bicycle has 1 lesser wheel than each tricycle.

Therefore, 20 ÷ 1 = 20 bicycles

56 – 20 00= 36 tricycles

36 – 20 = 16 more tricycles than bicycles

 

3–  $44

4–  22.5 km/h faster

Marcus’ speed –>  270 /4 = 67.5 km/h

Marcus’ new speed –>  270/3 = 90 km/h

90 km/h – 67.5 km/h = 22.5 km/h faster

 

5–  396 boys

Girls –>  1u × 5 = 5u

Boys –>  (1u + 16) × 3 = 3u + 48

8u + 48 –>  976 pupils

8u –>  928

1u –>  116

116 × 3 + 48 = 396 boys

 

6–  $2945

7 handbags + 5 watches = 3 handbags + 11 watches

7 handbags – 3 handbags = 11 watches – 5 watches

4 handbags = 6 watches

6 watches –>  $285 × 4 = $1140

1 watch –>  $1140 ÷ 6 = $190

$285 × 7 + $190 × 5 = $2945

 

7–  300 stickers

Maxwell –> 100%

Jeanetter –>  120%

20/100 × 120% = 24%

120%  – 24% = 96% left

96% –>  288 stickers

1% — 3 stickers

3 × 100 = 300 stickers

 

8–  153 cm

17 + 13 = 30 cm – 3 pieces

1 piece –>  10 cm

14 × 10 cm + 13 cm = 153 cm

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Primary 6 Prelims Revision 3

P6-Prelims-Ex 3

Ans:

1–  3 : 12 : 17

2–  4.95 cm

Length of the tank –>  180 cm³ ÷ 12 edges = 15 cm

33/100 × 15% = 4.95 cm

 

3–  100 balls

Total units of balls –>  5u + 4u = 9u

Units of balls in each bag in the end –>  9u/2 = 4.5u

5u – 4.5u = 0.5u —>  10 balls

1u –>  10 × 2 = 20 balls

20 × 5u = 100 balls

 

4–  540 km

5–  $24

1 blouse –>  1u

1 pair of jeans –>  1u + $12

3 pairs of jeans + 4 blouses –>  (1u + $12) × 3 + 4u = 7u + $36

7u + $36 ->  $204

7u –>  $204 – $36 = $168

1u –>  $24

 

6–  891 beads

Red : Blue + Green
4   :      5

Blue : Green
3    :    8     –>  11u

Adjust the units for the blue and green beads such that they are the same in both cases.

Common multiple of 5 and 11 is 55u

Therefore,

Red  :  Blue + Green
44   :      55

Blue  :  Green
15   :  40

Red  :  Blue  :  Green
44 :    15   :      40

44u – 40u = 4u –>  36 beads

1u –>  9 beads

44u + 55u = 99u —->  9 beads × 99 = 891 beads

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Primary 2 Whole Numbers Level 3 Ex 2

P2-Whole Numbers-L3-Ex 2

Ans:

1–  8 markers

 

2–  8 stamps

3–  569 stickers

4–  776 stamps

5–  40 pupils

Qn 5

Number of girls –> 30 ÷ 3 = 10

30 + 10 = 40 pupils

 

6–  9 beads

Total number of beads they had –>  76 + 45 = 121

130 – 121 = 9 beads

 

7–  720 stickers

Number of stickers Tanya has –>  341 + 38 = 379

379 + 341 = 720 stickers

 

8–  537 stamps

Primary 6 SA1 Revision 12

P6-SA1-Ex 12

Ans:

1–  175

2–  $43.50

70% of the price –>  $101.50

30% –>  $101.50/70 × 30 = $43.50

 

3–  (3+ 6) kg

Alan’s mass ->  (+ 3) kg

Nicholas’ mass ->  (m + 3) – 2 = (+ 1) kg

Brett’s mass ->  (+ 1) + 1 = (+ 2) kg

(m + 3) + (+ 1) + (+ 2) = (3+ 6) kg

 

4–  195 km

1  1/2 h× 80 km/h = 120 km

45/60 h × 100 km/h = 75 kg

120 km + 75 km = 195 km

 

5–  $6441.60

Earnings in January –>  122/100 × $6000 = $7320

Earnings in February –>  88/100 × $7320 = $6441.60

 

6–  30 people

Fraction of men  –>  30/100 = 3/10 = 9/30

Fraction of men if 10 women alighted –>  45/100 = 9/20

Women –>  30u – 9u = 21u

20u – 9u = 11u

10u –>  10 women

30 u –>  30 people

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Primary 2 Whole Numbers Level 3 Ex 1

P2-Whole Numbers-L3-Ex 1

Ans:

1–  241 marbles

2–  538 stamps

Number of stamps Irene has –>  325 – 112 = 213

325 + 213 = 538 stamps

 

3–  202 marbles

4–  40 pupils

5-  30 apples

Number of apples in each basket –>  2 + 3 = 5

5 × 6 = 30 apples

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Primary 3 Whole Numbers Level 3 Ex 4

P3-Whole Numbers-L3-Ex 4

Ans:

1–  4200 beads

Qn 1

Number of beads Jennifer has –>  1866 + 468 = 2334

2334 + 1866 = 4200 beads

 

2–  195 steps

3–  67 cookies

4–  a –>  1277 men   ,   b ->  1085 more men

Number of men who participated –>  1277 – 89 = 1188

Number of women who participated –>  123 – 20 = 103

1188 – 103 =1085 more men 

 

5–  5460 stickers 

Number of months from February to October –>  9

9 × 20 = 180 more than January

5280 + 180 = 5460 stickers

 

6–  $712

Total amount of money Melody and Lisa have –>  $2835 + $4259 = $7094

Amount of money each of them has in the end –>  $7094 ÷ 2 = $3547

$4259 – $3547 = $712

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Primary 5 October Problem Sums 5

P5-PSP-Oct-Ex5

Ans:

1–  $6588

2–  2400 cm³

Amount of water at first –>  4/5 × 30 cm × 20 cm × 30 cm = 14 400 cm³

Amount of water in the end –>  2/3 × 30 cm × 20 cm × 30 cm = 12 000 cm³

14 400 cm³ – 12 000 cm³ = 2400 cm³

 

3–  38 marbles

Qn 3

2u –>  96 – 60 = 36

Barry –>  36 ÷ 2 = 18 marbles

Joe –>  60 – 18 = 42 marbles

Tom –>  18 × 3 = 54 marbles

Total –> 54 + 42 + 18= 114 marbles

114 ÷ 3 = 38 marbles

 

4–  Cup Y —  160 ml    ,   Cup Z —  60 ml

Y   :   Z
8   :    3

8u + 3 = 11u

11u ÷ 2 = 5.5u

8u – 5.5u = 2.5u

2.5u –>  50 ml

1u –>  20 ml

Cup Y –>  20 ml × 8u = 160 ml

Cup Z –>  20 ml × 3 = 60 ml

 

5–  $651.80

Qn 5

2u –>  $1505 – $201.40 = $1303.60

$1303.60 ÷ 2 = $651.80

 

6–  $15.50

Qn 6

 

2u–  $108 – $71 = $37

1u —  $18.50

Megan –> $18.50 × 3 = $55.50

$71 – $55.50 = $15.50

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