"We just aimed for high marks."
Brittany's favourite subjects are chemistry and biology, while Charlotte says for her it is a tie between physics and biology.
"We don't have a least favourite subject."
Brittany, who received an Otago Leaders of Tomorrow Scholarship, and Charlotte, an Otago Dux Scholarship, say their secret is "to work hard all year".
They also played a big part in organising a Relay For Life team, and were involved with Stage Challenge, St Mary's ball and the leavers' dinner.
In 10 years' time they hope to be working overseas; meanwhile, they are setting their eyes on Otago University for next year, where both will study first-year health science and stay in Arana College.
The twins, who are from New Plymouth, each also received a Gold Award, together with Rachel Haire, Tegan Sharp and Abbe Shearer. This is the most prestigious award in the school awarded to students who most embody the characteristics of a St Mary's student: respect, responsibility, perseverance, service and care as well as being successful learners, resolute women and courageous leaders.
Lauren Terril and Emma Fitzgerald received the Sports Captains Trophy and Melissa Were was Sports Woman of the Year.