Average 2011 PSLE

The average of A, B and C  is 5y. C has 2 y more than B and A has y more than B.
a) Find B. Give your answer in terms of y.
b) If y = 5, what is B?


A [][   2 y   ]    )
B []                  ) 5 y x 3 = 15 y
C [][ y ]            )

3 u  -->  15 y  -  2 y  -  y  =  12 y

1 u --> 12 y ÷  3  =  4 y

a) It was  4 y.


4 x 5 = 20

b) It was 20.

Average PSLE 2010 P2 Q7

The table below shows the number of books read by each pupil in a class of 30 pupils. One of the numbers in the table is covered by an ink blot.


---------------------------------------------------------------
| Number of books read by each pupil   |   0   |   8   |  ??  |
---------------------------------------------------------------
| Number of pupils                                 |  10  |  15  |   5   |
---------------------------------------------------------------

The average number of books read by the pupils in the class is 6.


What is the number covered by the ink blot?


30  x  6  =  180


15  x  8  =  120


180  -  120  =  60


60  ÷  5  =  12

It is  12.

Average P6 2010 SA2 NY P2 Q14

Average P6 2010 SA2 HHK P2 Q17

The average length of 6 ropes was 80 cm. The average length of 4 of the ropes A,B, C and D was 15 cm more than the average length of the remaining 2 ropes E and F. (a) Find the average length of ropes E and F. Give your answer in metres. (b) If Rope E had been 18 cm shorter and Rope F had been 12 cm longer, they would have been of the same length. Find the actual length of Rope E. [5 marks][Answer given: 0.7m, 85 cm]


80 x 6 = 480

15 x 4 = 60

480 - 60 = 420

420 / 6 = 70 cm
            = 0.7 m

a) It was 0.7 m.


E [         ][    ][   18   ]      ] 70 x 2
F [         ][12]                   ] = 140 cm

2 u --> 140 - 12 - 18 = 110
1 u --> 110/2 = 55

55 + 12 + 18 = 85 cm

b) It was 85 cm.

Average P6 2009 SA2 P2 Rulang Q6

6.  100 people were having a health check at the Jurong Community Club. Their average mass was 63 kg. Given that the average mass of the women was 60 kg and the average mass of the men was 70 kg, how many men were there?

100 x 63 = 6300

100 x 60 = 6000

6300 – 6000 = 300

70 – 60 = 10

300 ÷ 10 = 30 men

There were 30 men.