How do you solve #10/k=8/4#?

1 Answer
Jim G.
Sep 3, 2016

#k=5#

Explanation:

We have one fraction equal to another. In this situation we can #color(blue)"cross-multiply"# to solve.

#rArrcolor(blue)(10)/color(red)(k)=color(red)(8)/color(blue)(4)#

Now cross-multiply(X) the values on either end of an 'imaginary' cross and equate them. That is multiply the #color(blue)"blue"# values together and the #color(red)"red"# values together and equate them.

#rArrcolor(red)(8k)=(color(blue)(10)xxcolor(blue)(4))rArr8k=40#

now divide both sides by 8 to solve for k.

#rArr(cancel(8)^1 k)/cancel(8)^1=(cancel(40)^5)/cancel(8)^1rArrk=5#

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