Page 56 - Maths Skills - 7

54 Maths

HOTS

1. Sonu works in an electronics showroom which sells TV sets. His salary is ` 10,000 per month. Sonu also
gets an incentive of ` 240 on every TV set he sells. Find the number of TV sets he should sell in order to
earn ` 14,320 next month.
2. Surbhi has borrowed 3 books from the library. The fine for not returning the books in time is ` 5 per
day. She remembers the librarian telling her that the Mathematics book was issued to her about
a week earlier than the two Science fiction books. If the total fine paid by Surbhi on all three books is
` 125, how long was each book overdue?
3. A mouse is 20 m away from its burrow and can run at 3 m per second. A cat spots the mouse and starts
running towards it at 6 m per second.

(i) How long will it take the mouse to reach its burrow?
(ii) If the cat is x metres away from the mouse as shown in figure next page, write an expression which
tells how long it will take the cat to reach the burrow.

(iii) If the cat pounces upon the mouse when it is about to enter its burrow, find the value of x.

Word Stock
Linear Equation Variable Solution Consecutive Balance
Transposition Root Interchange Exceed Statement Substituting

Activity

Objective: To understand a simple equation
Pre-Requisite Knowledge: Concept of Simple Equations

Materials Required: Pen, pencil
Instructions: 1. Divide the class into 5 groups (or more) and assign each group a value of a variable, say x.
Thus, we get teams with x = 2, x = 3, x = –1, etc. Teacher should prepare a bank of 50 simple
equations with variable and value of x as given to teams. She can take the help of the students
to form the equations. Number the equations 1 to 50 without the students knowing which
equation has which number.
2. The teams should have their value of the variable written on a circle of diameter of at least
20 cm looking like a cricket ball and display it prominently. The equations could also be
written out on thick paper in the shape of a cricket bat.

3. Each team will call out a number 1 to 50 turn by turn. Then the teacher writes the equation
corresponding to the number on the board. Students solve the equation and find which team's
value of x is the root of the equation. That team scores 10 points. This is continued further. The
team to score hundred points first is declared the winner.

4. Depending on time available the game could be of 50 points or 100 points, also depending on
strength of class, there could be 5 or more teams. If teams are more then number of equation
prepared should also be more. (about 10 equations per team at least.)