You estimate you can do 12 math problems in 45 minutes. How long should it take you to do 20 math problems?

1 answer:

7 0

$\bf \begin{array}{ccll} problems&minutes\\ \cline{1-2} 12&45\\ 20&x \end{array}\implies \cfrac{12}{20}=\cfrac{45}{x}\implies \cfrac{3}{5}=\cfrac{45}{x}\implies 3x=225 \\\\\\ x=\cfrac{225}{3}\implies x=75$

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Idk how to do this it’s so weird and I have no clue what to do

wolverine [178]

The equations in order from the first situation to the sixth situation are;

1. y = 2.5x, 2. y = 0.6x, 3. y = 2.33x, 4. y = 0.7x, 5. y = 1.6y and 6. y = 0.75.

Step-by-step explanation:

Step 1; Maya ate x grams and Hiram ate 1.5 times more. So if Maya ate x grams, Hiram ate 1.5x grams more than her. So Hiram ate, y = 1.5x + x = 2.5x.

So the equation is y = 2.5x.

Step 2; Hiram practiced piano for x hours and Maya practiced for $\frac{2}{5}$ less than that. So Maya practiced 0.4x hours lesser than Hiram. So Maya practiced for y = x - 0.4x = 0.6x hours.

So the equation is y = 0.6x.

Step 3; Maya drank x ounces of juice while Hiram drank $\frac{4}{3}$ more than that. So Hiram drank 1.33x ounces more than Maya. So Hiram drank, y = x + 1.33x = 2.33x.

So the equation is y = 2.33x.

Step 4; Hiram collected x pounds of recyclables while Maya collected $\frac{3}{10}$ less than that. So Maya collected 0.3x pounds lesser than Hiram. So Maya collected, y = x - 0.3x = 0.7x.

So the equation is y = 0.7x.

Step 5; Hiram completed x pieces of a puzzle while Maya completed $\frac{3}{5}$ more than that. So Maya completed 0.6x pieces more than Hiram. So Maya completed, y = x + 0.6x = 1.6x.

So the equation is y = 1.6x.

Step 6; Maya spent x dollars while Hiram spent $\frac{1}{4}$ dollars less than her. So Hiram spent 0.25x dollars less that Maya. So Hiram spent, y = x - 0.25x = 0.75x.