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Question

The following is one of the PSLE Math question this year 2019. I have 2 different answers for question (a). I was told the answer for fractions cannot be more than 1 whole. Could anyone advise if both answers are acceptable or only the fraction 11/32 is accepted? Thank you very much in advance.

 

The number of black beads was 1/3 of the white beads at first. After Amy used 1/4 of the black beads and 3/8 of the white beads,there were 63 beads left.

a)What is the fraction of the number of beads used?
b)How many beads were there at first?

Answer

“The following is one of the PSLE Math question this year 2019. I have 2 different answers for question (a). I was told the answer for fractions cannot be more than 1 whole. Could anyone advise if both answers are acceptable or only the fraction 11/32 is accepted? Thank you very much in advance.”

Whether or not the answer for a question on fractions could be more than a whole or not would depend on the actual question asked. If the answer is a fraction of a whole, then the answer obviously could not be more than a whole. For this question, only the fraction 11/32 is thus acceptable.

(a)
black beads : white beads
1 : 3
8 units : 24 units

(1/4) x 8 = 2 (black used)
8 – 2 = 6 (black left)
(3/8) x 24 = 9 (white used)
24 – 9 = 15 (white left)
2 + 9 = 11 (total used)
8 + 24 = 32 (total at first)

11/32 is the fraction of the number of beads used.

(b)
6 + 15 = 21
21 units = 63
1 unit = 3
32 units = 96

Ans : (a) 11/32 and (b) 96 beads.

 

1 Reply 1 Like

Thank you Mr alfretztay

1 Reply 0 Likes

You are welcome, Ms altp10.

0 Replies 0 Likes

This is a Before After question.                                              

  Before Transfer After
Black 8u -2u 6u
White 24u -9u 15u
  32u 11u 21u

1/4 =2/8

3/8 = 9/24

21u = 63

1u = 3

(a)  11/32

(b) 32u = 32 x 3 = 96

 

Table Method

 

 

 

1 Reply 1 Like

Thank you Mr Khong Pek Mao

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Quite obvious the 2nd answer for part A , i.e. 1 3/8 is wrong . Just logically speaking we can’t used a fraction of more than 1 whole. He/she needs to carry on to divide his answer with 4

1 3/8 => 11/8

11/8 divide by 4 = 11/32#

 

Did a short calculation, the first answer (Greenish tone) is  correct for both A and B.

1 Reply 1 Like

Thank you Mr Ender

0 Replies 0 Likes
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