A​ quantity, its three fourths

​, its one third
​, and its one fifth
​, added​ together, become 89.
What is the​ quantity in fraction form?

1 answer

Let the unknown quantity be represented by \( x \).

According to the problem, we have:

\[ x + \frac{3}{4}x + \frac{1}{3}x + \frac{1}{5}x = 89 \]

Now, we can combine these terms. To do this, we first need a common denominator for the fractions. The least common multiple (LCM) of \( 4, 3, \) and \( 5 \) is \( 60 \).

Now we can write each term with a denominator of \( 60 \):

\[ x = \frac{60}{60}x \]

\[ \frac{3}{4}x = \frac{3 \times 15}{4 \times 15}x = \frac{45}{60}x \]

\[ \frac{1}{3}x = \frac{1 \times 20}{3 \times 20}x = \frac{20}{60}x \]

\[ \frac{1}{5}x = \frac{1 \times 12}{5 \times 12}x = \frac{12}{60}x \]

Now we can combine these fractions:

\[ \frac{60}{60}x + \frac{45}{60}x + \frac{20}{60}x + \frac{12}{60}x = 89 \]

Adding the fractions gives us:

\[ \frac{60 + 45 + 20 + 12}{60}x = 89 \]

Calculating the numerator:

\[ 60 + 45 + 20 + 12 = 137 \]

So the equation simplifies to:

\[ \frac{137}{60}x = 89 \]

To isolate \( x \), multiply both sides by the reciprocal of \( \frac{137}{60} \):

\[ x = 89 \times \frac{60}{137} = \frac{5340}{137} \]

Thus, the quantity in fraction form is:

\[ \boxed{\frac{5340}{137}} \]