, MIP1501 Assignment 2 (COMPLETE ANSWERS) Semester
1 2025 - DUE 3 July 2025; 100% correct solutions and
explanations.
Question 1 (36)
1.1. Problem-Solving Level (6 marks)
1.1.1. Problem:
John had a few marbles. Today he played and doubled his number of
marbles. Then Thabo gave him three marbles for free. Jabu has 21
marbles now. How many did he have before he started playing?
Solution using a model:
Let’s use a bar model and let x represent the number of marbles John
had before he started playing.
1. He doubled the marbles: → 2×x2 \times x2×x
2. Then Thabo gave him 3 more marbles: → 2x+32x + 32x+3
3. Now he has 21 marbles:
So,
2x+3=212x + 3 = 212x+3=21
4. Solve the equation:
2𝑥 + 3 = 212𝑥 = 21 − 32𝑥 = 18𝑥 = 182𝑥 = 92𝑥 + 3
= 21 \\ 2𝑥 = 21 − 3 \\ 2𝑥 = 18 \\ 𝑥
= \𝑓𝑟𝑎𝑐{18}{2} \\ 𝑥 = 92𝑥 + 3 = 212𝑥
= 21 − 32𝑥 = 18𝑥 = 218𝑥 = 9
✅ Answer: John had 9 marbles before he started playing.
1 2025 - DUE 3 July 2025; 100% correct solutions and
explanations.
Question 1 (36)
1.1. Problem-Solving Level (6 marks)
1.1.1. Problem:
John had a few marbles. Today he played and doubled his number of
marbles. Then Thabo gave him three marbles for free. Jabu has 21
marbles now. How many did he have before he started playing?
Solution using a model:
Let’s use a bar model and let x represent the number of marbles John
had before he started playing.
1. He doubled the marbles: → 2×x2 \times x2×x
2. Then Thabo gave him 3 more marbles: → 2x+32x + 32x+3
3. Now he has 21 marbles:
So,
2x+3=212x + 3 = 212x+3=21
4. Solve the equation:
2𝑥 + 3 = 212𝑥 = 21 − 32𝑥 = 18𝑥 = 182𝑥 = 92𝑥 + 3
= 21 \\ 2𝑥 = 21 − 3 \\ 2𝑥 = 18 \\ 𝑥
= \𝑓𝑟𝑎𝑐{18}{2} \\ 𝑥 = 92𝑥 + 3 = 212𝑥
= 21 − 32𝑥 = 18𝑥 = 218𝑥 = 9
✅ Answer: John had 9 marbles before he started playing.
