课爱 classai 中文

Topics › Fractions › Q101

Fraction · using part of the remainder

P6 · Fractions · PSLE Maths

Question

Mei Ling brought some money to the school fair. She first spent 3/8 of it on games. Then she spent 2/5 of the remaining money on snacks. She had $36 left. How much money did Mei Ling have at first? How much did she spend altogether?

Try it yourself · watch the animation →

Hint

Draw the total money as 8 equal parts. After 3 parts are spent, 5 parts are left. Then split these 5 parts into the 2/5 spent and the final remainder.

Show the answer and step-by-step explanation

Answer: At first 96 $; Spent altogether 60 $

  1. Draw the whole — First, draw a bar for all the money Mei Ling had at first. Since she spent 3/8 first, split the whole bar into 8 equal parts.
  2. Find the remainder — After 3 parts are spent, 5 parts are left. The next fraction is 2/5 of the remaining money, so we now focus only on these 5 parts.
  3. Spend 2/5 more — From the 5 remaining parts, spending 2/5 means spending 2 parts on snacks. So 3 parts are left.
  4. Find 1 part — The final 3 parts are $36. So 1 part is $36 ÷ 3.
  5. Find the answers — She had 8 parts at first, so the amount was 8 × $12 = $96. Since $36 was left, she spent $96 − $36 = $60 altogether. 📌 Key idea: when a fraction of the remainder is used, split the bar step by step and match the final remaining units to the given amount.

Method: For remainder fraction problems, draw the model step by step: first a fraction of the whole, then a fraction of the remainder. Match the final remaining units to the given amount to find 1 unit.

Practice: 3 similar questions

  1. Ali brought some money to a book fair. He first spent 1/5 of it on notebooks, and then spent 3/4 of the remaining money on storybooks. He had $16 left. How much money did Ali have at first?
    Answer

    80 $ — After spending 1/5, 4/5 was left. Then he spent 3/4 of the remainder, so the final amount left was 1/4 of the remainder. The final amount left was 1/4 × 4/5 = 1/5 of all the money. 1/5 = $16, so all the money = $16 × 5 = $80.

  2. Raju had some marbles. He first gave 3/10 of them to his brother, and then gave 2/7 of the remaining marbles to his friend. He had 40 marbles left. How many marbles did he give to his friend?
    Answer

    16 marbles — After giving away 3/10, 7/10 remained. Then he gave away 2/7 of the remainder, so 5/7 of the remainder was left. The final amount left was 5/7 × 7/10 = 1/2 of all the marbles. 1/2 = 40 marbles, so the total was 80 marbles. After giving to his brother, 7/10 × 80 = 56 marbles remained. He gave his friend 2/7 × 56 = 16 marbles.

  3. Siti had some stamps. On Monday, she pasted 1/4 of them into her stamp album. On Tuesday, she pasted 2/3 of the remaining stamps into her album. She had 18 stamps left. How many more stamps did she paste on Tuesday than on Monday?
    Answer

    18 stamps — On Monday, she pasted 1/4, so 3/4 remained. On Tuesday, she pasted 2/3 of the remainder, so 1/3 of the remainder was left. The final amount left was 1/3 × 3/4 = 1/4 of all the stamps. 1/4 = 18 stamps, so the total was 72 stamps. On Monday, she pasted 1/4 × 72 = 18 stamps. On Tuesday, she pasted 2/3 × 54 = 36 stamps. She pasted 36 − 18 = 18 more stamps on Tuesday than on Monday.

Learn it on classai

An animation walks through each step, then 3 similar questions check it stuck; mistakes come back for review after 1, 3 and 7 days.

Open this question →

More Fractions questions