Solve Complex Fraction Division: 15/3 ÷ (12/8 ÷ (1⅘ ÷ 8))

Question

153:(128:(145:8))=? \frac{15}{3}:(\frac{12}{8}:(1\frac{4}{5}:8))=\text{?}

Video Solution

Solution Steps

00:00 Solve
00:03 Let's solve 15 divided by 3
00:08 Let's factor 12 into 4 and 3
00:11 Let's factor 12 into 4 and 2
00:23 Convert the whole number to fraction
00:27 Always solve parentheses first, the rule applies inside parentheses too
00:31 Simplify what's possible
00:40 Division is also multiplication by reciprocal (8 becomes one-eighth)
00:46 Division is multiplication by reciprocal
00:54 Make sure to multiply numerator by numerator and denominator by denominator
01:04 Division is multiplication by reciprocal
01:21 Simplify what's possible
01:25 Let's factor 9 into 3 and 3
01:34 Simplify what's possible
01:41 Let's factor 8 into 2 and 4
01:44 Simplify what's possible
01:47 And this is the solution to the question

Step-by-Step Solution

We solve the first fraction exercise:

153=5 \frac{15}{3}=5

We solve the second fraction by breaking it down into smaller multiplication exercises:

128=4×34×2=32 \frac{12}{8}=\frac{4\times3}{4\times2}=\frac{3}{2}

We convert the third fraction into a simple fraction:

145=95 1\frac{4}{5}=\frac{9}{5}

Now we obtain the exercise:

5:(32:(95:8))= 5:(\frac{3}{2}:(\frac{9}{5}:8))=

We note in inner parentheses the division exercise, a multiplication exercise between fractions:

5:(32:(95×18))= 5:(\frac{3}{2}:(\frac{9}{5}\times\frac{1}{8}))=

5:(32:95×8)= 5:(\frac{3}{2}:\frac{9}{5\times8})=

Now we invert the fraction to create a multiplication exercise:

5:(32×5×89)= 5:(\frac{3}{2}\times\frac{5\times8}{9})=

We combine the multiplication exercises, since it's just a multiplication operation:

5:3×5×82×9= 5:\frac{3\times5\times8}{2\times9}=

Now we invert the fraction to create a multiplication exercise:

5×2×93×5×8= 5\times\frac{2\times9}{3\times5\times8}=

We add the 5 to the numerator of the fraction in the multiplication exercise:

5×2×93×5×8= \frac{5\times2\times9}{3\times5\times8}=

We simplify the 5 in the numerator and denominator:

2×93×8= \frac{2\times9}{3\times8}=

We break down the 8 into a smaller multiplication exercise:

2×93×2×4= \frac{2\times9}{3\times2\times4}=

We simplify the 2 in the numerator and denominator:

93×4= \frac{9}{3\times4}=

We break down the 9 into a smaller multiplication exercise:

3×33×4= \frac{3\times3}{3\times4}=

We simplify the 3 in the numerator and denominator:

34 \frac{3}{4}

Answer

34 \frac{3}{4}