# Sarin participates in school anniversary event part 30 (Math Question)

Standard

The blog postings are about the Singapore Math. The readers can learn from the postings about 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 can learn the skills to deal with the Math Modeling, the Math Problem Solving 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 Fraction and Problem Solving.

Sarin learns concept of Fraction (Mathematics concept)

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

Upper primary school mathematics question UPQ586

Sarin used some red and yellow balloons to decorate the school hall for the school anniversary event. 2/3  of the red balloons and 6/7   of the yellow balloons were small balloons. If he had a total of 65 large balloons and 4/5  of them were red balloons, how many balloons did he has altogether?

Solution:

4/5  of the big balloons were red balloons,

5 units = 65

1 unit = 13

The number of big red balloons = 4 × 13 = 52

The number of big yellow balloons = 13

2/3  of the red balloons are small balloons,

Then

1/3  of the red balloons are small balloons

Total number of red balloons = 3 × 52 = 156

6/7  of the yellow balloons were small balloons,

Then,

1/7 of the yellow balloons were small balloons,

Total number of yellow balloons = 7 × 13 = 91

Total number of balloons = 156 + 91 = 247

Alternative solution(1):

By math model, Per the model,

5 units = 65

1 unit = 13

Total number of balloons = 19 × 13 = 247

Alternative solution(2) :

By ratio method,

2/3 of the red balloons are small balloons,

R(big) : R(small) : R = 1 : 2 : 3 = 4 : 8 : 12

6/7 of the yellow balloons were small balloons,

Y(big) : Y(small) : Y = 1 : 6 : 7

Since,

4/5 of the big balloons were red balloons,

R(big) : Y(big) : Big = 4 : 1 : 5

By matching R(big) to 4,

R(big) : Y(big) : R(small) : Y(small) : Big : Total = 4 : 1 : 8 : 6 : 5 : 19

Therefore,

5 units = 65

1 unit = 13

Total number of balloons = 19 × 13 = 247