If #y# varies inversely as #x# and #y=725# when #x=20#, what is #x# when #y# is 50?

3 Answers
Martha W.
Dec 22, 2017

#x=290#

Explanation:

if #y# varies inversely with #x#, then #y=k/x#
therefore #xy=k#

#20(725)=k#
#k=14,500#

when #y=50#, then #50x=14,500#
dividing both sides by #50# you get
#x=290#

Somebody N.
Dec 22, 2017

#290#

Explanation:

Inverse variation is given by:

#y=k/x^n#

Where #k# is the constant of variation.

First we find #k#.

From example:

#725=k/20=>k=20*725=14500#

When #y=50#

#:.#

#50=14500/x=>x=14500/50=color(blue)(290)#

Jim G.
Dec 22, 2017

#x=290#

Explanation:

#"the initial statement is "yprop1/x#

#"to convert to an equation multiply by k the constant"#
#"of variation"#

#rArry=kxx1/x=k/x#

#"to find k use the given condition"#

#y=725" when "x=20#

#y=k/xrArrk=yx=725xx20=14500#

#"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(y=14500/x)color(white)(2/2)|)))#

#"when "y=50#

#rArrx=14500/y=14500/50=290#

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