Multiplying integers word problems

Multiplying integers word problems: This lesson will show you how to solve five word problems related to the multiplication of integers.

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.