A number is [tex]\frac{2}{3}[/tex] of another number. If the sum of the two numbers is 30, find the smaller number. (Let the other number be [tex]x[/tex].)



Answer :

Sure! Let's solve the problem step-by-step.

1. Define the variables:
- Let the other number be [tex]\( x \)[/tex].
- The smaller number is [tex]\( \frac{2}{3} \)[/tex] of the other number, hence it is [tex]\( \frac{2}{3} x \)[/tex].

2. Set up the equation based on the given information:
- The sum of the two numbers is given as 30.
- Therefore, the equation is:
[tex]\[ x + \frac{2}{3} x = 30 \][/tex]

3. Combine like terms:
- To simplify this, we can combine the terms involving [tex]\( x \)[/tex]:
[tex]\[ x + \frac{2}{3} x = 30 \][/tex]
[tex]\[ \left(1 + \frac{2}{3}\right) x = 30 \][/tex]

4. Simplify the coefficient:
- We need to add the fractions:
[tex]\[ 1 + \frac{2}{3} = \frac{3}{3} + \frac{2}{3} = \frac{5}{3} \][/tex]
- Therefore, the equation becomes:
[tex]\[ \frac{5}{3} x = 30 \][/tex]

5. Solve for [tex]\( x \)[/tex]:
- To isolate [tex]\( x \)[/tex], multiply both sides by the reciprocal of [tex]\( \frac{5}{3} \)[/tex], which is [tex]\( \frac{3}{5} \)[/tex]:
[tex]\[ x = 30 \times \frac{3}{5} \][/tex]
- Perform the multiplication:
[tex]\[ x = \frac{90}{5} = 18 \][/tex]

6. Find the smaller number:
- The smaller number is [tex]\( \frac{2}{3} \)[/tex] of the other number [tex]\( x \)[/tex]:
[tex]\[ \text{Smaller number} = \frac{2}{3} \times 18 = 12 \][/tex]

So, the smaller number is [tex]\( 12 \)[/tex].