On my sister's 15th birthday, she was 159 cm in height, having grown 6% since the year before. How tall was she the previous year? Choose the most appropriate option.
A) 150 cm  B) 160 cm  C) 170 cm  D) 140 cm  E) 150 cm
Explanation:   Given that height on 15th birthday = 159 cm and growth = 6%   Let the previous year height = x   Then height on 15th birthday = x × (100 + 6)/100 = x × 106/100   ⇒159 = x × 106/100   ⇒x = 159 × 100/106 = 1.5 × 100 = 150 cm   150 cmnswer: Option 150 cm
<result>A</result>
On my sister's 15th birthday, she was 159 cm in height, having grown 6% since the year before. How tall was she the previous year?