GMAT Prep Q_Interest

[rohit9359]

Hi Guyz,

Refer attached. I think even statement (B) is sufficient to solve the Q. Could you please explain why OAis (A)?

Thanks much,
Rohit.

[jitendragneogi]

St 1.

plugging in the numbers.

210 = 1000 {(1+r/100)^2 - 1}
=> .21 = (1+r/100)^2
=> sqrt (.21) = 1 + r/100
=> r = real number

Sufficient to determine whether r>8.

St 2.

(1+r/100) ^ 2 > 1.15
=> (1 + r/100) > sqrt 1.15 or (1 + r/100) < sqrt 1.15
=> r can be having 2 positive values

Insufficient to determine whether r>8.

IMO A