Understanding the Missing Dollar Problem

Understanding the Missing Dollar Problem

Assessment

Interactive Video

Created by

Ethan Morris

Mathematics, English

5th - 8th Grade

Hard

The video presents a classic math puzzle where three friends buy pizzas for $30, but due to a special offer, the actual cost should be $25. The clerk returns $3 to the friends and keeps $2 as a tip, leading to confusion about a missing dollar. The video explains that the confusion arises from a flawed equation, and clarifies that the $27 paid includes the $25 for pizzas and a $2 tip, resolving the puzzle.

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10 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How much did each friend initially pay for the pizzas?

$8

$10

$9

$11

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What was the special offer price for the three pizzas?

$30

$25

$35

$20

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How much money did the clerk keep as a tip?

$4

$3

$2

$1

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the total amount the friends paid after receiving $1 back each?

$24

$25

$26

$27

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How much extra did the friends initially pay before the clerk's adjustment?

$5

$3

$6

$4

6.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the total amount returned to the friends by the clerk?

$4

$3

$2

$1

7.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the flaw in the logic that leads to the missing dollar confusion?

The pizzas were overpriced

The tip was added twice in the calculation

The clerk returned too much money

The friends paid too much initially

8.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the total amount the friends paid including the tip?

$25

$28

$26

$27

9.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What should be done to the $27 to find the correct cost of the pizzas?

Divide by 3

Multiply by 2

Subtract $2

Add $2

10.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the correct total cost of the pizzas after considering the tip?

$26

$25

$24

$23

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