NCERT Class 7 Solutions: Integers (Chapter 1) Exercise 1.1 – Part 2

Q-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?

Given the plane is flying at the height of 5000 m above the sea level and it is exactly above a submarine floating 1200 m below the sea level then find the vertical distance between them

Given the Plane Is Flying at the Height of 5000 M Above the Sea Level

Given the plane is flying at the height of 5000 m above the sea level and it is exactly above a submarine floating 1200 m below the sea level then find the vertical distance between them

Solution:

  • Height of plane above the sea level =5000m

  • Floating a submarine below the sea level =1200m

  • ∴The vertical distance between the plane and the submarine =5000+1200=6200m

  • Thus, the vertical distance between the plane and the submarine is 6200 m.

Q-5 Mohan deposits Rs. 2,000 in his bank account and withdraws Rs. 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 accounts after the withdrawal?

Solution:

  • Depositamount=Rs.2,000

  • Withdrawal amount is represented as negative integer =Rs.1,642

  • Balance=2,0001,642=Rs.358

  • Thus, the balance in Mohan’s account after withdrawal is Rs. 358.

Q-6 Rita goes 20 km towards east from a point A to the point B. From B, she moves 30 km towards west along the same road. If the distance towards east is represented by a positive integer then, how will you represent the distance travelled towards west? By which integer will you represent her final position from A?

Solution:

Let Rita move on a number line with point A as zero.

Given the Rita's travel distance from point A to B, if the distance towards east is represented by a positive integer then and find the which integer will you represent her final position from A

Given the Rita's Travel Distance From Point A to B

Given the Rita's travel distance from point A to B, if the distance towards east is represented by a positive integer then and find the which integer will you represent her final position from A

  • According to the number line, Rita moves towards east is represented by a positive integer. In this case point B would be 20 (20 km).

  • Later she moves in opposite direction means Rita moves west, this will be represented by negative integer -30 (30 km).

    Distance from A to B =20km

    Distance from B to C =30km

    Distance from A to C =2030=10km

    Thus, Rita is at final position from A to C is -10 km.

Q-7 In a magic square each row, column and diagonal have the same sum. Check which of the following is a magic square.

Given two magic square and in a magic square each row, column and diagonal have the same sum. check which of the following is a magic square

Given Two Magic Square

Given two magic square and in a magic square each row, column and diagonal have the same sum. check which of the following is a magic square

Solution:

Understand that the sum of a positive number and a negative number results in subtraction operation.

  1. 1st magical square

    • Taking Rows

      • Taking 1st row =5+(1)+(4)=514=55=0

      • Taking 2nd row =(5)+(2)+7=52+7=7+7=0

      • Taking 3rd row =0+3+(3)=33=0

    • Taking Columns

      • Taking 1st column =5+(5)+0=55=0

      • Taking 2nd column =(1)+(2)+3=12+3=3+3=0

      • Taking 3rd column =(4)+7+(3)=4+73=7+7=0

    • Taking diagonals

      • Taking 1st diagonal =5+(2)+(3)=523=55=0

      • Taking 2nd diagonal =(4)+(2)+0=42=6

      This box is not a magic square because all the sums are not equal.

  2. 2nd t magical square

  • Taking Rows

    • Taking 1st row =1+(10)+0=110=9

    • Taking 2nd row =(4)+(3)+(2)=432=9

    • Taking 3rd row =(6)+4+(7)=6+47=13+4=9

  • Taking Columns

    • Taking 1st column =1+(4)+(6)=146=110=9

    • Taking 2nd column =(10)+(3)+4=103+4=13+4=9

    • Taking 3rd column =0+(2)+(7)=27=9

  • Taking diagonals

    • Taking 1st diagonal =1+(3)+(7)=137=110=9

    • Taking 2nd diagonal =0+(3)+(6)=36=9

    This box is a magic square because all the sums are equal.

Explore Solutions for Mathematics

Sign In