Page 52 - Math Smart - 7

I have y marbles and I divide them equally between 4 friends.

Each one gets (y -i- 4) or ^ marbles.

y

Example 2

A banana costs b cents and a watermelon costs w cents. Write down an
expression for the cost of
a) 5 bananas,
b) 3 watermelons,
c) 5 bananas and 3 watermelons
in cents.

b cents w cents
Solution
Cost of:
a) 5 bananas = Sx b = Sb cents
b) 3 watermelons = 3 x w = 3w cents
c) 5 bananas and 3 watermelons = (Sb + 3iv) cents

Example 3

1 don't know. But know
I
Do you know
that his brother, Peter, is
how old 3ohn is?
2 years older than him.

How old is John?
Solution
y + 2 means we add 2 to John's age is unknown. We can represent it using the letter y.
John's age. John is >• years old. So, Peter is (y + 2) years old.

We can also represent Peter's age using the letter z.
z-2 means we subtract 2
from Peter's age. If Peter is - years old, John is {z - 2) years old.

•• Think and Share

The area of a rectangle is the product of its length and breadth. Let
A, .V and _v represent the area of the rectangle, its length and breadth
respectively.
a) Write the formula of the area of the rectangle.
b) If the length of the rectangle is 10 units and the breadth is 6 units,
what is its area?
c) Write the formula of the perimeter of the rectangle.

4aj UNITS introduction to Algebra and Equations