HOTS Mathematics Primary 6 Algebra

Nadia and Siti each had some money. The ratio of Nadia's money to Siti's money was 7 : 4. After Nadia spent $21 and Siti saved an extra $9, they had the same amount of money. How much money did Nadia have at first?

A $28
B $40
C $49
D $70
Show Worked Solution

Worked Solution

Step 1: Set up the ratio using a variable. Let Nadia's money = 7k and Siti's money = 4k. Step 2: Write the equation using the equal-amount condition. After Nadia spends $21: Nadia has 7k − 21. After Siti saves $9: Siti has 4k + 9. They are equal: 7k − 21 = 4k + 9 Step 3: Solve for k. 7k − 4k = 9 + 21 3k = 30 k = 10 Step 4: Find Nadia's original amount. Nadia = 7k = 7 × 10 = $70 Step 5: Verify. Nadia: $70 − $21 = $49. Siti: $40 + $9 = $49. Equal. ✓ Answer: $70

Correct answer: $70

Want more questions like this? Superholic Lab has 10,000+ MOE-aligned questions with full worked solutions.

Start Free Trial — 7 Days Free