How do you solve #6.1p = 4.5#?

2 Answers
Dec 28, 2016

#p =0.7377# to 4 decimal places.

Explanation:

#6.1p = 4.5#

divide both sides by #6.1# to make only #p# alone on left side.

#(cancel6.1p)/cancel6.1 = 4.5/6.1#

#p = 0.7377#

Dec 30, 2016

#p=45/61#

Calculation method given in a lot of detail.

Explanation:

#color(blue)("Method")#

Think of the given equation as:#" "6.1xxp=4.5#

If you can change the 6.1 into 1 then the left hand side would become:#" "1xxp# and 1 times any number does not change its value.

In equations, what you do to one side of the = you do to the other side to maintain correct proportions (ratio)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Answering the question")#

Divide each side by 6.1#color(white)(.)# (#color(white)(.)# this is the same as multiply by #color(blue)(1/6.1 )color(white)(.)#)

#color(brown)(" "6.1p" "=" "4.5)#

#color(brown)(color(blue)(1/6.1xx)6.1xxp" "=" "color(blue)(1/6.1xx)4.5)#

#color(brown)(" "6.1/(color(blue)(6.1))xxp" "=" "4.5/(color(blue)(6.1)))#

But #6.1/6.1=1# giving:

#color(brown)(" "1xxp" "=" "4.5/(color(blue)(6.1)))#

#color(brown)(" "p" "=" "4.5/(color(blue)(6.1)))#

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If you divide 4.5 by 6.1 you get a very 'long' decimal value and if you round this down or up you will not be as precise as #4.5/6.1#. So lets keep this as a fraction. However decimal values in fractions is not good practice so lets change this to whole numbers.
................................................................................................................................
#color(white)(.)#

#color(green)(4.5/6.1" " =" "[4.5/6.1color(red)(xx1)]" "=" "[4.5/6.1color(red)(xx10/10)]" "=" "45/61 )#

So write the solution as:

#" "color(blue)(p=45/61)#