If x varies directly as y, and x = 10 when y = 7, find y when x = 50.?

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If x varies directly as y, and x = 10 when y = 7, find y when x = 50.?

2007-12-01 06:41:48 · 4 answers · asked by jared r 1 in Science & Mathematics ➔ Mathematics

4 answers

x = ky
10 = 7k
k = 10 / 7
y = (1/k) x
y = (7/10) 50
y = 35

2007-12-01 08:19:55 · answer #1 · answered by Como 7 · 3⤊ 1⤋

x = 10 when y = 7
x = 50 y = ?

y = 50/10 * 7 = 5 * 7 = 35

2007-12-01 14:44:03 · answer #2 · answered by A Little Sarcasm Helps 5 · 1⤊ 2⤋

There is not enough information to determine the equation.
When x varies directly as y, we know y = kx + c.
x = 10 when y = 7 means 7 = 10k + c.
But that's only one equation, we need another point to solve for both k and c.

2007-12-01 14:45:19 · answer #3 · answered by xiaodao 4 · 1⤊ 1⤋

x=ky for some k
10=k(7)
k=10/7
50=(10/7)y
y=350/10=35

2007-12-01 14:52:38 · answer #4 · answered by cidyah 7 · 1⤊ 3⤋