GMAT Math Practice Test #1

Answer C

Use simple algebra rules ( √5 + √5 )² = (√5) ² (1 + 1) ² = 5 x 4 =20

Key takeaway: The square root of the numbers like √5 is a decimal number and expression would require long calculation if we put in the given. So look for a way to attack such problems other way than straight arithmetic calculation. You should be able to find some factors or application of simple algebraic formulae.