Question #bd490

2 Answers
Apr 7, 2017

See the entire solution process below:

Explanation:

"Percent" or "%" means "out of 100" or "per 100", Therefore 45% can be written as #45/100#.

When dealing with percents the word "of" means "times" or "to multiply".

Finally, lets call the number we are looking for "n".

Putting this altogether we can write this equation and solve for #n# while keeping the equation balanced:

#72 = 45/100 xx n#

#color(red)(100)/color(blue)(45) xx 72 = color(red)(100)/color(blue)(45) xx 45/100 xx n#

#7200/color(blue)(45) = cancel(color(red)(100))/cancel(color(blue)(45)) xx color(blue)(cancel(color(black)(45)))/color(red)(cancel(color(black)(100))) xx n#

#160 = n#

72 is 45% of #color(red)(160)#

Apr 7, 2017

The number is #160#

Explanation:

Calculations with percent can always be done by using direct proportion.

In this case we know that #72# represents #45%# and we want to know what number represents #100%#

#72 " " rarr 45%#
#x" "rarr 100%#

#x/72 = 100/45" "larr# cross multiply and solve for #x#

#45x = 72 xx 100#

#x = (72xx100)/45#

#x = 160" "larr# this is the #100%#

NOTE:

When we divide #72 " by " 45# we are finding #1%#

Once we know the value of #1%#, multiply by #100#

#72/45 xx 100 = 1.6 xx 100 = 160#