Leah has [tex]$28$[/tex] more marbles than Dan. One third of Leah's marbles is equal to [tex]$\frac{4}{5}$[/tex] of Dan's marbles. How many marbles does Leah have?



Answer :

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

1. Let \( D \) be the number of marbles Dan has.

2. Leah has 28 more marbles than Dan. Therefore, if \( L \) represents the number of marbles Leah has, we can express this relationship as:
[tex]\[ L = D + 28 \][/tex]

3. According to the problem, one third of Leah's marbles is equal to \(\frac{4}{5}\) of Dan's marbles. We can write this as the following equation:
[tex]\[ \frac{L}{3} = \frac{4}{5} D \][/tex]

4. Substitute \( L \) from step 2 into the equation in step 3:
[tex]\[ \frac{D + 28}{3} = \frac{4}{5} D \][/tex]

5. To clear the fractions, multiply both sides of the equation by 15 (the least common multiple of 3 and 5):
[tex]\[ 15 \cdot \frac{D + 28}{3} = 15 \cdot \frac{4}{5} D \][/tex]
This simplifies to:
[tex]\[ 5 (D + 28) = 12 D \][/tex]

6. Distribute and simplify the equation:
[tex]\[ 5D + 140 = 12D \][/tex]

7. Isolate \( D \) by subtracting \( 5D \) from both sides of the equation:
[tex]\[ 140 = 7D \][/tex]

8. Solve for \( D \):
[tex]\[ D = \frac{140}{7} = 20 \][/tex]

So, Dan has 20 marbles.

9. Now, use this value of \( D \) to find out how many marbles Leah has:
[tex]\[ L = D + 28 = 20 + 28 = 48 \][/tex]

Therefore, Leah has 48 marbles.

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