Question

Find the cost of painting a rectangle board of length \[50\] cm and breadth \[20\] cm at the rate of rupees \[15\] per sq.cm.

Answer 1

Hint: In this question we are going to find the total rupees needed to paint the rectangle board. To find the total rupees we should know the area of the rectangle board to be painted. The board is in rectangle shape, is a closed figure with four sides where the length of the opposite sides are equal and parallel to each other. Thus we can say that a rectangle comprises two sides, the length of the rectangle is the longest side and breadth (or width) of the rectangle is the shortest side. And the area of the rectangle depends on its length and breadth.
Formula used:
Area of the rectangle board \[ = length \times breadth\]

Complete step-by-step answer:
In this problem,
We are given that,
Length of the rectangle board \[l = 50\] cm.
Breadth of the rectangle board \[b = 20\] cm.
We have the formula for the area of a rectangle, \[area = l \times b\].
By the formula, area of the rectangle board \[ = length \times breadth\]
\[ = 50 \times 20\]
\[ = 1000\]
Therefore the total area of the rectangle board to be painted is \[1000{cm^2}\]
Also given that the rate to be painted per sq.cm \[ = 15\]RS.
The cost to paint \[1000{cm^2}\] \[ = 1000 \times 15\]
\[ = 15000\]
The total cost to paint the \[1000{cm^2}\] area of a rectangle board is rupees \[15000\].
So, the correct answer is “Rs 15000”.

Note: To find the total cost multiply the total area with the rupees per sq.cm. Remember that the units of all the terms should be the same.
If the units are different, convert the units of terms into the same to attain the correct answer because calculating the different units of terms will collapse the result.
In this problem the unit used by both the length and breadth is ‘cm’ and thus the unit of area is ‘cm square.