The World of Numbers | Exercise 3.2

Question 2

A spice trader takes a loan (debt) of ₹850. The next day, he makes a profit (fortune) of ₹1,200. The following week, he incurs a loss of ₹450. Write this sequence as an equation using integers and calculate his final financial standing.

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Solution

We will represent financial transactions using positive and negative integers.

Step 1 — Forming the equation

A loan or debt means money owed. We represent debt as a negative integer. So, a debt of ₹850 is -850.

A profit means money gained. We represent profit as a positive integer. So, a profit of ₹1,200 is +1200.

A loss means money lost. We represent loss as a negative integer. So, a loss of ₹450 is -450.

To find the final standing, we add these values. The equation representing the sequence is: 850+1200450-850 + 1200 - 450

850+1200450\boxed{-850 + 1200 - 450}

Diagram 1

Step 2 — Calculating the final standing

Now, let's calculate the total. We add the numbers from left to right. 850+1200450-850 + 1200 - 450 =350450= 350 - 450

100 ₹\boxed{-100 \text{ ₹}}

Answer

(i) The equation representing the sequence is: 850+1200450-850 + 1200 - 450. (ii) His final financial standing is 100-₹100.

More questions in Exercise 3.2

Q1

The temperature in the high-altitude desert of Ladakh is recorded as 4 °C at noon. By midnight, it drops by 15 °C. What is the midnight temperature?

Q2

A spice trader takes a loan (debt) of ₹850. The next day, he makes a profit (fortune) of ₹1,200. The following week, he incurs a loss of ₹450. Write this sequence as an equation using integers and calculate his final financial standing.

Q3

Calculate the following using Brahmagupta's laws:

(i) (12)×5(-12) \times 5

(ii) (8)×(7)(-8) \times (-7)

(iii) 0(14)0 - (-14)

(iv) (20)÷4(-20) \div 4

Q4

Explain, using a real-world example of debt, why subtracting a negative number is the same as adding a positive number (e.g., 10(5)=1510 - (-5) = 15).

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