Answer:
B. 40 minutes
Step-by-step explanation:
I know for a fact that this is the correct answer. I just took a test with this same question and got it right. Let me know if you would like more explanation, but if you are just looking for the answer for a test or something, I promise you the answer is B. 40 minutes.
The number of the minutes to plant all 70 flowers will be 40 minutes. Then the correct option is B.
Suppose the given points are (x₁, y₁) and (x₂, y₂), then the equation of the straight line joining both two points is given by
[tex]\rm (y - y_1) = \left [ \dfrac{y_2 - y_1}{x_2 - x_1} \right ] (x -x_1)[/tex]
Caroline is planting flowers in her garden. She plants her first 7 flowers in 4 minutes. After 12 minutes, she has planted 21 different flowers.
Then the coordinate will be (4, 7) and (12, 21).
(x₁, y₁) → (4, 7)
(x₂, y₂) → (12, 21)
Let x be the number of the minutes and y be the number of the planting flowers.
Then the equation of line passing through (4, 7) and (12, 21) will be
y – 7 = [(21 – 7) / (12 – 4)] (x – 4)
y – 7 = (14 / 8) (x – 4)
y – 7 = (7 / 4) (x – 4)
y – 7 = (7/4)x – 7
y = (7/4)x
If Caroline keeps planting flowers at this rate.
Then the number of the minutes to plant all 70 flowers will be
y = (7/4)x
70 = (7/4)x
10 = x / 4
x = 10 × 4
x = 40
Thus, the number of the minutes to plant all 70 flowers will be 40 minutes.
Then the correct option is B.
Learn more about straight-line equations here:
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