# Sarin participates in school anniversary event part 15 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings about Solving Singapore Primary School Mathematics. The blog presenting the Math Concept, Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can learn the skills to deal with Math Modeling, Math Problem Solving and 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 Ratio and Problem Sum.

Read the posting on Sarin participates in school anniversary event part 1 for story on school anniversary.

To read also the posting on Sarin learns concept of ratio in school to understand the concept of Ratio.

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

Upper primary school mathematics question UPQ311

Sarin’s teacher gave two boxes of pens to Sarin for the team to use during the anniversary event.  Box X has twice as many pens as Box Y. All the pens in Box X are red. There are red and blue pens in Box Y. In Box Y, the ratio of the number of red pens to the number of blue pens is 5 : 6. What is the fraction of the total number of pens in both boxes are red? Give your answer in the simplest form.

Solution:

In Box X are all red pens and are twice as many pens as Box Y

The ratio of red pens to blue pens in BoxY is 5 : 6

Redraw the model

The fraction of the total number of pens in the boxes are red = 27/33 = 9/11

Alternative solution:

Ratio of number of pens in box X to Box Y is 2 : 1

Box X : Box Y = 2 : 1 = 22 : 11

In box Y, the number of red pens to blue pens is 5 : 6

Red Y: Blue Y : Box Y = 5 : 6 : 11

Box X : Red Y : Blue Y : Box Y = 22 : 5 : 6 : 11

All the pens in box X are red pens

Box X = Red X

Red X : Red Y : Blue Y : Box Y = 22 : 5 : 6 : 11

Red X + Red Y : Box X + Box Y = 27 : 33

The fraction of the total number of pens in the boxes are red = 27/33 = 9/11