2007-11-02 11:05:38 · 4 answers · asked by batty_starr 2 in Science & Mathematics ➔ Mathematics
Since they vary directly, set them up as a pair of ratios in the same direction:
42 .... x
---- = ---
7 ...... 8
Now cross multiply:
7x = 42 * 8
Divide both sides by 7:
x = 42 * 8 / 7
x = 6 * 8
x = 48
So the answer is x = 48
Notice how x is 6 times y in both ratios.
2007-11-02 11:10:09 · answer #1 · answered by Puzzling 7 · 1⤊ 0⤋
If x=42 and y=7, then y=x/6 or x=6y
So if y=8 then x=48
2007-11-02 18:09:01 · answer #2 · answered by Bryan B 2 · 2⤊ 0⤋
48
2007-11-02 18:10:43 · answer #3 · answered by §Broken.Shattered.Untouched§ 4 · 0⤊ 0⤋
x/y = costant
x/8 = 42/7 = 6
Multiply both sides by 8,
x = 48
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Ideas: Direct variation means the ratio is a constant.
2007-11-02 18:09:00 · answer #4 · answered by sahsjing 7 · 0⤊ 1⤋