Question

Does anyone know how to solve U/5+U/20+U/6=1

Answer 1

between 5 20 and 6
can you give me a number that all those 3 guys can divide it?

Answer 2

I cant think of a number that can be divided into each number

Answer 3

\(\bf \square \div 5\qquad \square \div 20 \qquad \square \div 6\)

Answer 4

Wait I wrote the problem wrong .. It's suppose to be \[\frac{ U }{ 5 } + \frac{ U }{ 10} + \frac{ U }{ 6 } = 1\]

Answer 5

so would it be 30

Answer 6

\(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}=1\implies \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}=\cfrac{1}{1} \)

Answer 7

so your denominators are 5, 10, 6 and 1
the LCD will be the a number that's divisible by all 4 of those guys,
I initially didn't include "1" because any number is divisible by 1

Answer 8

well, let's try 30 \(\bf 30 \div 5 = 6\qquad \qquad 30 \div 10 = 3\qquad \qquad 30 \div 6 = 5\)

Answer 9

So saying That all of the denominators have to be the same?

Answer 10

well, let us use the LCD, there's an easier method but .... let's see this one
so \(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}=\cfrac{1}{1} \implies \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}-\cfrac{1}{1}=0\\
\cfrac{\square+\square+\square-\square}{30}\)

Answer 11

do you know what goes atop?

Answer 12

0?

Answer 13

\(\bf \cfrac{\square+\square+\square-\square}{30}=0\) rather

Answer 14

So I have to find numbers that will add and subtract together and be divided by 30 to equal 0

Answer 15

\(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}-\cfrac{1}{1}=0 \implies
\cfrac{\left(\frac{30}{5}\right)u+\left(\frac{30}{10}\right)u+\left(\frac{30}{6}\right)u-\left(\frac{30}{1}\right)u}{30}\)

Answer 16

when adding fractions, you use LCD, divide it by the fraction's denominator's and multiply the quotient by the numerator, that goes up there, in the resulting fraction

Answer 17

hmm, the last one has no "u"... lemme fix that

Answer 18

\(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}-\cfrac{1}{1}=0 \implies
\cfrac{\left(\frac{30}{5}\right)u+\left(\frac{30}{10}\right)u+\left(\frac{30}{6}\right)u-\left(\frac{30}{1}\right)}{30}\)

Answer 19

also forgot to equate to 0, ohh well, anyhow the last fraction is really unnecessary, but anyhow

Answer 20

So I wouldn't have to put \[\frac{ 30 }{ 1 }\]

Answer 21

well, I could have written it as \(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}=1 \implies
\cfrac{\left(\frac{30}{5}\right)u+\left(\frac{30}{10}\right)u+\left(\frac{30}{6}\right)u}{30} = 1\)

Answer 22

and once you get your numerator above, you can always cross-multiply

Answer 23

the result will be the same, just less clutter

Answer 24

so what would be the result

Answer 25

what did you get in the numerator?

Answer 26

Will there be 3 different numbers?

Answer 27

should, yes

Answer 28

So I have 2, 3, 2

Answer 29

30/5 = 2? 30/6 = 2? \(\bf \cfrac{\left(\color{red}{\frac{30}{5}}\right)u+\left(\color{red}{\frac{30}{10}}\right)u+\left(\color{red}{\frac{30}{6}}\right)u}{30} = 1\)

Answer 30

My bad .. I meant .. 6 and 5

Answer 31

\(\bf \cfrac{u}{5}+\cfrac{u}{10}+\cfrac{u}{6}=1 \implies
\cfrac{\left(\frac{30}{5}\right)u+\left(\frac{30}{10}\right)u+\left(\frac{30}{6}\right)u}{30} = 1 \\
\cfrac{6u+3u+5u}{30}=1\implies
\cfrac{14u}{30} = 1\)

now solve for "u"

Answer 32

I get huge decimal when I solve for u

Answer 33

well, don't use a decimal :), leave it as fraction

Answer 34

So \[\frac{ 14u }{ 30 } = 1 \] is the answer

Answer 35

no, you'd need to solve it for "u"

Answer 36

How?

Answer 37

or isolate "u" that is

Answer 38

http://www.youtube.com/watch?v=_A8lLbZCrlw

Answer 39

so would you do the reciprocal?

Answer 40

you 'd multiply both sides by 30, then
divide both by 14

Answer 41

I got 2.14

Answer 42

if you use decimals, yes

Answer 43

Okay. we do .