Question

If the breadth of a rectangle is increased by 40% and the length is reduced by 30%. What will be the effect on its area ?

• A. Decreases by 2%
• B. Increases by 2%
• C. Increases by 10%
• D. Decreases by 10%

Answer 1

Answer:

A. Decreases by 2%

Let:

• Length = (L)

• Breadth = (B)

Original area:

$A = L \times B$

After changes:

• New Length = (0.7L) (30% decrease)

• New Breadth = (1.4B) (40% increase)

New area:

$A' = 0.7L \times 1.4B = 0.98LB = 0.98A$

Change in area:

$\text{Decrease} = A - A' = 1 - 0.98 = 0.02 = 2\%$

The area decreases by 2%.