Tegan bought 1 1/6 metres of ribbon. She needs 2/5 meters to wrap her brothers present and 3/4 meters to wrap her sister's present. Did she buy enough ribbon?

Respuesta :

Answer:

Yes, Tegan buys enough ribbon.

Step-by-step explanation:

Given:

Length of ribbon bought by Tegan = [tex]\frac{11}{6}[/tex] = [tex]1.83[/tex] meters

Ribbon needed to wrap her brother's present = [tex]\frac{2}{5}[/tex] meters

Ribbon needed to wrap her sister's present = [tex]\frac{3}{4}[/tex] meters

Let the length of ribbon needed for wrapping be 'x' meters

So,

⇒ [tex]x=\frac{2}{5} +\frac{3}{4}[/tex]

⇒ Taking LCD of [tex]5[/tex] and [tex]4[/tex] that is [tex]20[/tex].

⇒ [tex]x=\frac{(2\times 4)+(3\times 5)}{20}[/tex]

⇒ [tex]x=\frac{8+15}{20}[/tex]

⇒ [tex]x=\frac{23}{20}[/tex] meters

Comparing  [tex]\frac{23}{20}[/tex] and [tex]\frac{11}{6}[/tex].

LCD of [tex]20[/tex] and [tex]6[/tex] is [tex]60[/tex].

Now equating the denominators.

⇒ [tex]\frac{23\times 3}{20\times 3} = \frac{69}{60}[/tex]  and  ⇒ [tex]\frac{11\times 10}{6\times 10} =\frac{110}{60}[/tex]

Now we can compare the above like fractions.

⇒  [tex]\frac{69}{60}[/tex] < [tex]\frac{110}{60}[/tex]

Shortcut:

We can directly compare the factions by cross multiplying.

⇒ [tex]\frac{23}{20} \ \ \ \ \ \ \ \ \ \frac{11}{6}[/tex]

⇒ [tex]23\times 6[/tex] , [tex]20\times 11[/tex]

⇒ [tex]138[/tex] and [tex]220[/tex]

⇒ [tex]138[/tex] < [tex]220[/tex]

Then

⇒ [tex]\frac{23}{20}[/tex] < [tex]\frac{11}{6}[/tex]

She has enough ribbon to wrap the presents as ribbon bought by Tegan is greater in length than the ribbon used.