CLASS-7 chapter-1 exercise-1.1-
Answers
Step-by-step explanation:
1. Following number line shows the temperature in degree celsius (co) at different places on a particular day.
(a) Observe this number line and write the temperature of the places marked on it.
Solution:-
By observing the number line, we can find the temperature of the cities as follows,
Temperature at the Lahulspiti is -8oC
Temperature at the Srinagar is -2oC
Temperature at the Shimla is 5oC
Temperature at the Ooty is 14oC
Temperature at the Bengaluru is 22oC
(b) What is the temperature difference between the hottest and the coldest places among the above?
Solution:-
From the number line we observe that,
The temperature at the hottest place i.e., Bengaluru is 22oC
The temperature at the coldest place i.e., Lahulspiti is -8oC
Temperature difference between hottest and coldest place is = 22oC – (-8oC)
= 22oC + 8oC
= 30oC
Hence, the temperature difference between the hottest and the coldest place is 30oC.
(c) What is the temperature difference between Lahulspiti and Srinagar?
Solution:-
From the given number line,
The temperature at the Lahulspiti is -8oC
The temperature at the Srinagar is -2oC
∴The temperature difference between Lahulspiti and Srinagar is = -2oC – (8oC)
= – 2OC + 8oC
= 6oC
(d) Can we say temperature of Srinagar and Shimla taken together is less than the
temperature at Shimla? Is it also less than the temperature at Srinagar?
Solution:-
From the given number line,
The temperature at Srinagar =-2oC
The temperature at Shimla = 5oC
The temperature of Srinagar and Shimla taken together is = – 2oC + 5oC
= 3oC
∴ 5oC > 3oC
So, the temperature of Srinagar and Shimla taken together is less than the temperature at Shimla.
Then,
3o > -2o
No, the temperature of Srinagar and Shimla taken together is not less than the temperature of Srinagar.
2. In a quiz, positive marks are given for correct answers and negative marks are given
for incorrect answers. If Jack’s scores in five successive rounds were 25, – 5, – 10,
15 and 10, what was his total at the end?
Solution:-
From the question,
Jack’s score in five successive rounds are 25, -5, -10, 15 and 10
The total score of Jack at the end will be = 25 + (-5) + (-10) + 15 + 10
= 25 – 5 – 10 + 15 + 10
= 50 – 15
= 35
∴Jack’s total score at the end is 35.
3. At Srinagar temperature was – 5°C on Monday and then it dropped by 2°C on Tuesday. What was the temperature of Srinagar on Tuesday? On Wednesday, it rose by 4°C. What was the temperature on this day?
Solution:-
From the question,
Temperature on Monday at Srinagar = -5oC
Temperature on Tuesday at Srinagar is dropped by 2oC = Temperature on Monday – 2oC
= -5oC – 2oC
= -7oC
Temperature on Wednesday at Srinagar is rose by 4oC = Temperature on Tuesday + 4oC
= -7oC + 4oC
= -3oC
Thus, the temperature on Tuesday and Wednesday was -7oC and -3oC respectively.
4. A plane is flying at the height of 5000 m above the sea level. At a particular point, it is exactly above a submarine floating 1200 m below the sea level. What is the vertical distance between them?
Solution:-
From the question,
Plane is flying at the height = 5000 m
Depth of Submarine = -1200 m
The vertical distance between plane and submarine = 5000 m – (- 1200) m
= 5000 m + 1200 m
= 6200 m
5. Mohan deposits ₹ 2,000 in his bank account and withdraws ₹ 1,642 from it, the next day. If withdrawal of amount from the account is represented by a negative integer, then how will you represent the amount deposited? Find the balance in Mohan’s account after the withdrawal.
Solution:-
Withdrawal of amount from the account is represented by a negative integer.
Then, deposit of amount to the account is represented by a positive integer.
From the question,
Total amount deposited in bank account by the Mohan = ₹ 2000
Total amount withdrawn from the bank account by the Mohan = – ₹ 1642
Balance in Mohan’s account after the withdrawal = amount deposited + amount withdrawn
= ₹ 2000 + (-₹ 1642)
= ₹ 2000 – ₹ 1642
= ₹ 358