How do you find a number which exceeds 10 by as much as twice the number exceeds 38?

2 Answers
Dec 28, 2016

Write an equation: 2x-38 = x-102x38=x10

Solve it to find x=28x=28

Explanation:

Let the unknown number be xx

Twice the number exceeds (is more than) 38.
This difference can be written as: 2x-382x38

The number exceeds 10.
This difference can be written as:x-10x10

The two differences are equal to each other.

You can now write an equation showing this information.

2x-38 = x-10" "larr2x38=x10 now solve the equation for xx

2x-x = -10+382xx=10+38

x =28" "larrx=28 This is the number

Let's check:

2xx28-38 = 182×2838=18

28-10 = 182810=18

The differences are the same.

Dec 28, 2016

Depending upon how you translate the given statement,
the number is either 2828 or 6666.
(see below)

Explanation:

Let the number be represented by the variable nn

There are two possible interpretations of the given statement:

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Interpretation 1

color(red)("a number which exceeds 10")color(green)(" by as much as")color(blue)(color(magenta)(" twice the number")" exceeds 38")a number which exceeds 10 by as much as twice the number exceeds 38

color(red)("a number which exceeds 10 ")color(green)(=)color(blue)(color(magenta)(" twice the number")" exceeds 38")a number which exceeds 10 = twice the number exceeds 38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)(" twice the number")" exceeds 38")n10= twice the number exceeds 38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)(2n)" exceeds 38")n10=2n exceeds 38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)(2n)-38)n10=2n38

Subtract nn from both sides
-10=n-3810=n38

Add 3838 to both sides
28=ncolor(white)("XXXX")or n=2828=nXXXXorn=28

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Interpretation 2

color(red)("a number which exceeds 10")color(green)(" by as much as")color(blue)(color(magenta)(" twice")" the number exceeds 38")a number which exceeds 10 by as much as twice the number exceeds 38

color(red)("a number which exceeds 10 ")color(green)(=)color(blue)(color(magenta)(" twice")" the number exceeds 38")a number which exceeds 10 = twice the number exceeds 38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)(" twice")" the number exceeds 38")n10= twice the number exceeds 38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)("twice ")n-38)n10=twice n38

color(red)(n-10)color(green)(=)color(blue)(color(magenta)2(n-38)n10=2(n38)

Expanding the right side
color(red)(n-10)= 2n-76n10=2n76

Subtract nn from both sides
-10=n-7610=n76

Add 7676 to both sides
66=ncolor(white)("XXXX")or n=6666=nXXXXorn=66