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Question

So the problem is: If the ratio of red flowers to yellow flowers in the local park is 9:5 and there are approximately 1,000 red or yellow flowers currently blooming in the park, about how many of them are yellow? You may need to round to the nearest whole number" ^^How do you set that up?

Answer 1

Put red is denoted by r and yellow is denoted by y then

The ratio of red flowers to yellow flowers in the local is 9 : 5

r : y = 9 : 5 or r / y = 9 / 5 or 5r = 9y

There are  red or yellow flowers are 1000(approximately)

The total no of red and yellow flowers are 1000

Therefore r + y = 1000

Multiply each side by 5

5r + 5y = 5000

Substitute 5r = 9y then

9y + 5y = 5000

14y = 5000

Divide each side by 14

y = 5000 / 14

y = 357.14

Round to the nearest whole number is 357

y = 357 (approximately)

The yellow flowers are 357.

 

Answer 2

Let r and y are the number of red and yellow flowers respectively.
total flowers = r + y = 1000 --------- (1)
ratio of red flowers to yellow flowers = 9/5
ratio = r / y = 9/5
find the cross products
5r = 9y ---------- (2)
multiply the equation (1) by 5
5r+5y = 5000
replace 5r = 9y
9y+5y = 5000
14y = 5000
y = 5000/14 = 357
r = 1000 - y = 1000 -357 = 643
red flowers currently blooming in the park = 643
yellow flowers currently blooming in the park = 357