S has 3/5 as many members as F, So there is 42 members in S and 70 members in F.

that step already finished Zhong Shu Hao

only for every 3 members who joined the swim club , 1 member joined. that line don't know how to produce.

Initially, S:F 3:5 In the end, S:F 5:3 -----> 15:9

so there was a 12 units increase in S, and a 4 units increase in F. So, 3 units --> 42 1 unit --> 14 In the end, No of people in S = 15 units = 15 x 14 = 210 people No of people in F = 9 units| = 9 x 14 = 126 people

Hi, why do we multiply by 3 to get 15:9?

Because we want the final ratio to have a "relationship" with the starting ratio, where the difference between the two numbers for S is 3 times the difference between the 2 numbers for F.

Hi zhong shu hao, thank you for your kind explanation. After adding the additional members in a different ratio, the original ratio had changed. How do we explain that the relationship btw the 2 number for S is not altered with 3:1 members added?

Thanks Zhong Shu Hao. But I also cannot understand why to multiply by 3 to get 15: 9. kindly can you explain.

I used algebra to cheat a bit actually... But overall idea is that for the new ratio, 5:3, I must change it to 5parts:3parts, such that 5parts - 3units is 3 times of 3parts - 5units.

Thank you so much for your effort Mayuree Thongpan. I could understand now.

The question said

The figure below is made of a circle , a rectangle and a triangle. The ratioof the shaded area to the unshaded area of the circle is 3:5. 4/15 of the rectangle and 50% of the triangle is shaded. The total area of the circle and triangle is 2/3 the area of the rectangle

the total are is 630cm2

What is the ratio of the area of circle to the area of rectangle to the area of triangle

What is the area of the circle

Hi is the ans for A) 8:15:2 ?

part A ik how to do but idk part B

B) 378cm2 ?

Is the answer: 472.5?

Not very sure...

Thks 😊

Write down the beginning and end ratio. Total is the same. Work out the equivalent ratios and you should get the answer

Thks all 😊