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P5 Mathematics

Question post on Mon, 24/04/2017 4:49pm

Colleen and Shin Sian shared some chocolates in the ratio 5 : 4. Their teacher gave both of them some more chocolates. For every 2 pieces of chocolate Colleen received, Shin Sian received 1 piece. Eventually, the ratio of the number of chocolates Colleen had to the number of chocolates Shin Sian had was 3 : 2. How many pieces of chocolates did they have altogether in the end if Shin Sian received 12 pieces of chocolates from their teacher?

Answer

alfretztay · Answer 1 · Post on Tue, 25/04/2017 8:42am

At first,
Colleen : Shin Sian
5u : 4u

Teacher gave,
Colleen : Shin Sian
2 : 1
24 : 12

Eventually,
Colleen : Shin Sian
3p : 2p

5u + 24 ——- 3p
20u + 96 ——- 12p
4u + 12 ——- 2p
20u + 60 ——- 10p
12p – 10p = 2p ——- 96 – 60 = 36
1p ——- 36/2 = 18
3p + 2p = 5p ——- 18 x 5 = 90

Ans : 90 pieces of chocolates.

siglapmath · Answer 2 · Post on Mon, 24/04/2017 11:39pm

siglapmath Post on Mon, 24/04/2017 11:39pm

siglapmath · Answer 3 · Post on Mon, 24/04/2017 11:39pm

siglapmath

Post on Mon, 24/04/2017 11:39pm

zihao99 · Answer 4 · Post on Mon, 24/04/2017 9:14pm

C : S
5 : 4 (initial) Let each unit be u
3 : 2 (final) Let each unit be v

If Shin Sian received 12 pieces of chocolates, Colleen received 2 × 12 = 24 pieces of chocolate.

5u + 24 = 3v
⇒ v = 5/3 u + 8
4u + 12 = 2v
⇒ v = 2u + 6

Combining both equations,
⟶ 5/3 u + 8 = 2u + 6
⇒ 1/3 u = 2
⇒ u = 6

Initially, they have 5 + 4 = 9u
⇒ 9u = 9 × 6 = 54

They received 12 + 24 = 36 chocolates from their teacher.

∴ In the end, they have 54 + 36 = 90 chocolates altogether