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3 years ago

If y varies directly as x and y = 21 when x = 5, find x when y = 42.

Mathematics

1 answer:

Lorico [155]3 years ago

5 0

Answer: 10

<u>Step-by-step explanation:</u>

varies directly means: $\frac{y}{x} = k$

Step 1: solve for k ⇒ $\frac{21}{5} = k$

Step 2: plug in the given value and k to solve for the missing value: $\frac{42}{x} = \frac{21}{5}$

42(5) = 21(x)

$\frac{42(5)}{21} = \frac{21(x)}{21}$

2(5) = x

10 = x

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