Hairu shares his stickers part 60 (Math Question)

Standard

The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. The blog presents the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids will learn the skills of dealing with the Math Problem Solving, the Math Modeling and the Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Percentage and Problem Sum.

You should read the posting on Sarin learns Average Number, Percentage and Charting in school (Math Concept) to understand Percentage.

Challenge yourself with the question before look out for the given solution‼!

Upper primary school mathematics question UPQ470

Hairu had 20% more stickers than Sarin. Fatimah had 40% fewer stickers than Hairu. Fatimah lost 25% of her stickers and she had 540 stickers left. Sarin bought some stickers and the number of stickers that he had increased by 10%. How many stickers did the three children have on the end?

Solution:

Fatimah lost 25% of her stickers and left with 540 stickers

3 units = 540

1 unit = 180

The number of stickers that Fatimah has at first = 4 × 180 = 720

Fatimah had 40% fewer stickers than Hairu

From the model

3 units = 720

1 unit = 240

The number of stickers that Hairu has at first = 5 × 240 = 1200

Hairu had 20% more stickers than Sarin at first

From the model,

6 units = 1200

1 unit = 200

The number of stickers that Sarin has at first = 5 × 200 = 1000

The final number of stickers that Sarin had was 10% more

From the model

10 units = 1000

1 unit = 100

The number of stickers that Sarin has at the end = 11 × 100 = 1100

The number of stickers that the three children had at the end = 540 + 1200 + 1100 = 2840

Alternative Solution:

Fatimah lost 25% of her stickers and left 540 stickers

75% ==> 540

10% ==> 72 stickers

100% ==> 720 stickers

At first,

The number of stickers Hairu has = 720 ÷ 0.6 = 1200

The number of stickers Sarin has = 1200 ÷ 1.2 = 1000

The number of stickers Fatimah has = 720

At the end,

The number of stickers Hairu has = 1200

The number of stickers Sarin has = 1000 × 1.1 = 1100

The number of stickers Fatimah has = 540

The total number of stickers three of them have = 1200 + 1100 + 540 = 2840