Multiplying Integers Word Problems

Multiplying integers word problems: This lesson will show you how to solve eight word problems related to the multiplication of integers and four more below you can read on your own. Read the solutions carefully, so you will know how to do similar problems.

In each worked example above, every part of the story becomes a positive or a negative integer. Then you multiply the integers and use the sign rules to answer the question. The worked examples will help you see how to turn each part of a story into an integer step by step, decide whether the answer is positive or negative, and get ready for the practice problems and the quiz below. Click through the steps one at a time.

Four More Interesting Multiplying Integers Word Problems

Problem #1

From sea level, a submarine descends 40 feet per minute. Where is the submarine in relation to sea level 5 minutes after it starts descending?

Solution

In 1 minute, the submarine is 40 feet below sea level. This situation can be represented with -40 feet. Notice that we use a negative sign since the submarine is descending.

After 5 minutes, the submarine is at -40 × 5 = -200 feet

Problem #2

The price of one share of a stock fell 4 dollars each day for 8 days. How much value did one share of the stock lose after 8 days?

Solution

Each day, one share of the stock goes down by 4 dollars. We can represent this situation with the integer -4 dollars.

After 8 days, one share of a stock has gone down by -4 × 8 = -32

One share of a stock is now worth 32 dollars less.

Problem #3

A test has 20 questions. The test awards 3 points if the answer is correct and takes away 1 point if the answer is incorrect. A student answered 5 questions incorrectly. How many points did the student lose?

Solution

For each incorrect answer, the student gets -1 point.

After answering 5 questions incorrectly the student get -1 × 5 = -5.
The students lost 5 points after answering five questions incorrectly.

Problem #4

A credit card company charges a late fee of 25 dollars each time a customer fails to pay on time. A customer missed the payment 4 times last year. At the customer's request and out of courtesy, the credit card company decides to cancel all late fees for that year. Write a numerical expression to show how much money was return.

Solution

The amount of late fee the bank charged last year was -25 × 4

In order to return the money, the bank can do this math: -25 × -4

Notice how the number 4 became negative. This is necessary so the amount of money the customer gets back is a positive number.

Did you have a hard time understanding the word problems above? If so, do not worry. Check also the word problem below and go over the ones above one more time.