RRB Group-D Model Paper 18 with answers for online practice

Tips & Tricks
GIVEN:
Dimension of square is increased by 10%
CONCEPT:
Here calculate the new area and then subtract it by original to calculate the percentage.
FORMULAE USED:
Area of new square = ${\left(\mathit{s}\mathit{i}\mathit{d}\mathit{e}\right)}^2$
SOLUTION:
Let the side of square be a cm
Area of square = ${\left(\mathit{a}\right)}^2$
Side is increase by 10%
New side = (110/100) × a = 1.1a
Area of new square = 1.21a2
Area of square increases by
⇒ [(1.21a – 1a)/a] × 100 = 21%
∴ Area of square is increased by 21%