Bob the builder is making 480 kg of concrete mix

Mathematics

2 answers:

Marina CMI [18]3 years ago

6 0

Answer:

180 kg

Step-by-step explanation:

The ratio is

cement : sand : gravel

1 : 3 : 4

If he used 1 kg cement, 3 kg sand, and 4 kg gravel, he'd get 8 kg of concrete.

He wants to make 480 kg of concrete.

480/8 = 60

He needs 60 times more concrete than the numbers in the ratio.

60 * 3 kg = 180 kg

Answer: 180 kg

svetoff [14.1K]3 years ago

4 0

Answer:

If sand is 3 in the ratio, it is 180kg

Step-by-step explanation:

480/8=60 60 times 3 is 180

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Answer:

K = -72

Step-by-step explanation:

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Read 2 more answers

Solve 2x+3y=2<br> 5x-y=-29<br> By elimination

Andreyy89

Answer:

$\huge\boxed{x=-5,\ y=4\to(-5,\ 4)}$

Step-by-step explanation:

$\left\{\begin{array}{ccc}2x+3y=2\\5x-y=-29&\text{multiply both sides by 3}\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}2x+3y=2\\15x-3y=-87\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad17x=-85\qquad\text{divide both sides by 17}\\.\qquad\dfrac{17x}{17}=\dfrac{-85}{17}\\.\qquad\boxed{x=-5}\\\\\text{Substitute it to the second equation:}\\\\5(-5)-y=-29\\\\-25-y=-29\qquad\text{add 25 to both sides}\\\\-25+25-y=-29+25\\\\-y=-4\qquad\text{change the signs}\\\\\boxed{y=4}$