How do you evaluate #\frac { 4} { n } = \frac { 80} { 100}#?

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Answer 1 · 2018-05-11T12:45:36

#n=5#

Shortcut method:

Turn everything upside down giving:

#n/4=100/80#

Multiply both sides by 4.

#n=(100xxcancel(4color(white)(.))^1)/cancel(80)^20#

#n=5#

Answer 2 · 2018-05-11T12:57:31

#n=5#

#4/n=80/100#

#:."swop the denominator and nominator on L.H.S and R.H.S."#

#:.n/4=100/80#

#:."multiply L.H.S and R.H.S by 4"#

#:.(cancel 4^1n)/cancel 4^1=(4xx100)/80#

#:.n=cancel 400^5/cancel 80^1#

#:.n=5#

~~~~~~~~

#:."check:-"#

#:.4/(5)=cancel 80^4/cancel 100^5#

#:.4/5=4/5#