Question

Find the cost of putting a ribbon around a rectangular frame with length 90 cm and breadth 60 cm if the ribbon costs Rs. 10/metre.

• A. Rs. 20
• B. Rs. 30
• C. Rs. 34
• D. Rs. 28

Answer 1

The correct option is B Rs. 30

We are putting a ribbon on the boundary of the frame, so we must calculate the perimeter of the frame.
Perimeter of rectangular frame = 2 $\times$ (length + breadth)
= 2 $\times$ (90 + 60)
= 2 $\times$ 150
= 300 cm.
Now we are given the cost of the ribbon for metres, so we must convert the perimeter to metre.
300 cm / 100 = 3 metres
Cost of 1 metre of ribbon = Rs. 10
Cost of 3 metres of ribbon = Rs. 3 x 10 = Rs. 30